## How to Tame a Cockatiel

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Tame cockatiels can be great fun for petting, playing, or even dancing to music, but it can take some time and effort to get to that point. When taming cockatiels, it’s important to proceed slowly, training him or her in short sessions and in a quiet area. If your cockatiel is young, you are likely to have more luck and move faster in training.

## EditSteps

### EditSocializing a Cockatiel

1. Stay quiet and unobtrusive around a new cockatiel. Do not attempt begin taming until it has spent a few weeks getting accustomed to its new environment. Keep the cockatiel in a quiet, calm area.
2. Talk to the cockatiel from outside the cage. You may say anything you like, as long as your voice stays calm, without sudden changes in volume. Also try to speak softly, not loudly. Lower yourself to just above the cockatiel’s eye level if you are taller than its cage, putting yourself in a less threatening position without appearing submissive. Keep this up for a few days before you make any attempt to train the bird.
3. Make sure your bird is comfortable with you. At some point, now that your bird is used to the sound of your voice, he or she will begin to move toward you when you sit down to talk to your cockatiel. At this point, you can begin to train your bird, but only very slowly.[1]
4. Offer the cockatiel a treat. A spray of millet is commonly used to train cockatiels, since the birds are typically enthusiastic about the food, but you may use any cockatiel-appropriate food in small amounts. Hold it through the bars of the cage, but not directly at its face. This encourages the bird to make its way toward you voluntarily. Keep it steady as the bird pecks once or twice, or let it peck for up to five seconds when it demonstrates unusually good behavior.[2]
• Only use the spray of millet, or whichever treat you chose, as a treat. The cockatiel may be less motivated for training if it can eat the same food without working for it.
5. Repeat this routine daily. Each day, set aside some time to talk to the cockatiel, keep your hand steady near the bird, then give it a treat if it calms down. Spend no more than 10 or 15 minutes per session, one or two times a day, to avoid making cockatiel anxious. At the end of each session, make the cockatiel move closer to your hand before it can get the treat.
• Even if a young bird is willing to play with you and appears happy, keep these sessions to no more than 15 minutes, as a young bird needs to return to its cage to eat and rest frequently.

### EditTeaching Your Cockatiel to Step Up

1. Open the cage only when the cockatiel is comfortable. Once the bird is comfortable around you, it will stay calm as you approach it, and may even eat the treat directly from your hand. This may take weeks or months for an adult bird that is not used to close human interaction. Once you’ve reached this stage, you may convince the cockatiel to leave its cage, although some older birds that did not grow up socialized may not voluntarily do this.
• Make sure all windows and doors in the room are closed, and no other pets are present, before you open the cage.
2. Continue moving your hand closer during training sessions. Once the bird will approach you and eat from your hand, start approaching it in a similar way with an empty hand, extending two fingers horizontally. Hold the hand in position until the bird calms down, rewarding a bird with a treat if the cockatiel remains calm. Again, keep these sessions to 10 or 15 minutes, once or twice each day.
3. Get the bird to step onto your finger. Eventually, move your hand directly to the bird’s perch, or touch its feet. Once you can keep your hand there without agitating the bird, gently push the bird’s lower chest with your fingers. A light nudge should be enough to slightly knock the cockatiel off balance, and cause it to step on your finger with one foot.
4. Encourage the behavior. Each time the bird starts to step up, say a short command such as “step up” or “up.” Praise the bird and give it a small treat when it does this. Praise again when bird steps with both feet. Keep training sessions to a few minutes at a time, making sure to always end on a positive note.
• The cockatiel may use its beak to test the stability of your finger. Try not to jerk your hand away when the beak touches your finger.
5. Teach the cockatiel to step down and ladder. Once the bird will step onto your finger on command, teach it to “step down” onto another perch using the same method.[3] Reinforce these behaviors by teaching it to “ladder,” or repeat the “step up” command from your left hand to your right and back again.[4] Train the bird to perform these movements daily, until it will do so on command without a treat.
• You do not need a special command for laddering. Repeat the “step up” command instead.

### EditTraining for Other Tricks

1. Consider clicker training. As the training gets more complicated, your bird may have trouble figuring out why you are giving it a treat. Try using a “clicker,” or make a distinct, short sound by tapping a pen, each time the bird displays good behavior. This gets the bird’s attention while you fetch a treat. Once the bird is well trained, you can use just the sound of the clicker or pen as a reward, but until then the treat is still a vital part of the training.
• A clicker or other distinct sound is recommended over a verbal command, because it sounds the same each time and is unlikely to be encountered outside of training.
2. Continue using clicker training for additional tricks. Clicker training remains an excellent tool for training pets. Whenever you start teaching the cockatiel a new command, use a clicker or make a distinctive noise by tapping a pen at the moment it shows good behavior. Fetch a treat immediately afterward, and continue daily training until the cockatiel will respond to the command with just the clicker as a reward.
3. Teach the cockatiel to be comfortable in a towel. If the cockatiel is comfortable outside its cage, put it on a white or beige towel on floor each day during its training session. Gradually bring up the corners of the towel, but stop if the bird struggles. Repeat the process each day, rewarding the bird when it stays calm, until you can fully enclose the cockatiel in the towel.[5] This training will make it much easier to bring your cockatiel to the vet, or remove it from a dangerous situation.
4. Teach the cockatiel to talk. Repeat a phrase a few times, with an animated facial expression and tone, at a time when the cockatiel is relaxed and happy. If the cockatiel looks at you and demonstrates a reaction, such as cocking its head or dilating its pupils, it may be interested in that word. Repeat that word frequently, but stop if the cockatiel gets bored. When it attempts to mimic you, reward it with a treat.[6]
• Male cockatiels can make more sounds than females, since they use more complex calls to attract mates. Female cockatiels can still talk, but the voice may not be as clear.
• Most cockatiels can talk around eight months of age, although you can attempt to teach them as young as four months if the bird appears interested.[7] It can be harder to train an adult bird not used to speaking.
5. Encourage the bird to whistle and dance. While watching the cockatiel, bob your head or rock your finger back and forth to music with a steady beat. When it starts to rock back and forth, reward it with a clicker and a treat. As you continue this training, and find music that gets the cockatiel’s attention, it may sway more energetically and raise its wings while doing so.[8] Similarly, whistling during these dance sessions may encourage the cockatiel to make sounds of its own.

### EditDealing with Biting

1. Try not to react when bitten. If the cockatiel bites you, try to keep your reaction to a minimum. Jerking away violently, responding loudly, or ending the taming session can encourage the bird to bite again. This can be difficult to avoid due to the painful bite, so try to avoid serious bites in the first place by leaving the cockatiel alone when it is hissing, when it has fully extended its head crest, or when its crest is flattened against its head.[9]
• Wear thick gardening gloves if biting is a recurring problem.
2. Don’t try to punish the cockatiel. Cockatiels do not typically understand what you are doing when you attempt to punish them. They may enjoy it when you shout at them, return them to their cage, or otherwise react to bad behavior. Focus on praising the cockatiel during good behavior instead, or use mild forms of punishment such as ignoring the bird, or gently withdrawing the jewelry it is nibbling.[10]
3. Only pet the cockatiel if it remains calm. Many cockatiels will only let you pet their crest or beak, and some dislike any form of petting. Pet slowly, and withdraw slowly if the bird hisses, nips at you, or flattens its crest.

## EditTips

• Train the bird in a quiet area with just the two of you around, to minimize distractions.
• Cockatiels test things that catch their interest by using their beak and tongue. If the cockatiel’s crest is half-raised, and the beak is exploring rather than pinching shut, the behavior is likely a sign of curiosity, not hostility.[11]

## EditWarnings

• Never grab the bird forcefully, especially from behind. Cockatiels are capable of turning around to bite you.

## EditSources and Citations

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## How to Cook Asparagus

Fresh asparagus, packed full of potassium, calcium, iron and vitamins A and C, is a nutritious complement to nearly any meal. It tastes best gently cooked to preserve its light, fresh taste and a hint of crunch. For a full understanding of the capacity of asparagus, try cooking it in a variety of ways to find the method that fits your taste.

## EditSteps

### EditPrepping Asparagus

1. Choose thick or thin spears. Thin asparagus cook quickly and tend to have a crisp exterior and soft center, while thick asparagus take a bit longer to cook and have a bulkier texture. Either type of asparagus is excellent no matter how you cook it, with the main difference being the final texture. Just be sure to choose asparagus that’s fresh, green and firm – not floppy or discolored – when you’re picking it out at the market.
• Thick asparagus often has a slightly woodier stem, which you may want to peel before cooking. To peel an asparagus, just take a vegetable peeler and lightly stroke it from the middle of the asparagus to the base.
• Thin asparagus is a good choice for use in salads or stir fries.
2. Wash fresh asparagus under cool running water. Asparagus is grown in sand, so it might have some sandy residue left in the cracks and crevices. Hold it under running water for a few moments. If sand is hiding in the tips, fill a large bowl with cool water, then dunk the asparagus in the water until the sand is removed.
3. Break off the ends. The base of the asparagus is tough and woody, and not very tasty when it’s cooked. The easiest way to figure out how much to take off is to feel it by hand. Hold each asparagus spear with two hands and gently bend it until you feel the spot where it gives, then break the spear. Discard the tough, white end.
• If you don’t have the time to break each spear, place the bunch of asparagus on a cutting board and chop off about from the bottom of the spears.
• If you choose to peel the asparagus, just chop about off of the ends.

### EditBlanching, Steaming or Boiling

1. Blanch the asparagus. This is a common way to quickly cook asparagus to perfection and serve it cold in salads or as a luncheon side dish. If you’d prefer to serve the asparagus warm, skip the ice water bath. Here’s how to blanch asparagus:
• Boil a large pot of water and 2 teaspoons of salt.
• Place the asparagus in the water and let it cook for 2 1/2 – 3 minutes.
• Test an asparagus spear for doneness – it should still be crispy, not limp.
• If you wish, plunge the asparagus in a bowl of ice water to cool it down.[1]
2. Steam asparagus in a vegetable steamer basket. For a quick, flavorful side dish, steaming is the way to go. it preserves the asparagus’ nutrients and crisp texture.
• Place about of water in a saucepan, and place a steamer basket in the pan.
• Heat the water to a boil.
• Break the asparagus into lengths that easily fit in the steamer.
• Place the asparagus into the basket, cover and steam for 5 to 7 minutes, until they’re bright green and still crisp.
3. Boil asparagus. This is an easy way to cook asparagus, but you have to be careful not to overcook the spears. They can quickly become limp and mushy if you aren’t careful.
• Place a few inches of water and 2 teaspoons salt in a saucepan.
• Bring the water to a full boil.
• Place the asparagus spears in the boiling water.
• Once the water returns to a boil, cook for 5 minutes.
• If you wish, use a microwave-safe cooking dish to boil asparagus in the microwave. Fill the cooking dish with 1/4 cup water, then add the spears and place the lid on the dish. Cook the asparagus on your microwave oven’s high power setting for 3 minutes, then open the door and stir. Finish cooking until the spears are just barely tender, about 3 to 4 more minutes.

### EditSautéing

1. Cut the asparagus or leave the spears whole. If you want to make a stir fry, slice the spears into 1 to 2-inch pieces for stir-fry, making the cuts diagonally.
2. Heat oil in a saucepan. Place about 1 tablespoon of oil or butter in a saucepan, and heat it over medium-high heat.
3. Add the asparagus to the pan. Carefully place the asparagus in the pan. Use a wooden spoon or spatula to stir-fry it until it’s tender, about 3 to 6 minutes. The asparagus is ready when it’s bright green with a few charred spots.
• If you’re making a stir fry, add other vegetables to the pan at the same time. Carrots, onions, green peppers, and mushrooms are all delicious served in a stir fry with asparagus.
4. Season the asparagus. Sauteed asparagus is delectable with lemon juice and butter drizzled over the top. Season with salt and pepper to taste.

### EditRoasting

1. Preheat the oven to 400 degrees. Make sure the oven is completely preheated before you put the asparagus inside – otherwise they’ll steam instead of roasting.
2. Place the asparagus spears on a baking sheet. Arrange them in a single layer so that they’ll cook evenly.
3. Drizzle olive oil over the spears. The oil will help the asparagus stay crisp. Drizzle 2 tablespoons of olive oil evenly over the spears on the baking sheet.
• If you’d like to ensure the spears get evenly coated, you can toss them with the olive oil in a bowl, then arrange them on the baking sheet.
4. Season with salt and pepper. Sprinkle salt and pepper to taste over the asparagus spears. To take the dish up a notch, grate some Parmesan cheese over the asparagus, too.
5. Roast for 12 minutes. Place the asparagus in the oven and roast it for 12 minutes, until it turns bright green and appears charred in a few places. Take care not to overcook it, as it will quickly burn if left in the oven for too long.
6. Enjoy!

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## EditTips

• An herb butter is delicious on asparagus prepared any way. To make a simple herb butter, place 1 tbsp. of boiling water in a small bowl. Stir in about 1/2 tsp. (2.5 g) of your favorite dry herbs, such as rosemary, thyme, basil or tarragon. Add 4 tbsp. (60 g) softened butter and stir to mix.
• Purchase firm asparagus spears with tightly closed tips. Fresh asparagus is deep green, and doesn’t appear wilted or soft.
• To store asparagus, wrap a moist paper towel loosely around the bottom of the asparagus. Place the asparagus in a plastic bag, then store in the vegetable drawer in your refrigerator. Asparagus has the best flavor if used within 3 days after purchase.
• To make asparagus salad, combine 1 lb. (0.5 kg) of cooked, cooled asparagus with a sliced tomato and a small, thinly sliced onion. Toss the asparagus salad with oil and vinegar, or use your favorite Italian salad dressing. Chill, then serve cold.

## EditThings You’ll Need

• Large bowl
• Saucepan
• Vegetable steamer basket
• Microwave-safe cooking dish with lid
• Knife
• Wok or skillet
• Cooking oil

## EditSources and Citations

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## How to Find Extrema of Multivariable Functions

In single-variable calculus, finding the extrema of a function is quite easy. You simply set the derivative to 0 to find critical points, and use the second derivative test to judge whether those points are maxima or minima. When we are working with closed domains, we must also check the boundaries for possible global maxima and minima.

Since we are dealing with more than one variable in multivariable calculus, we need to figure out a way to generalize this idea.

## EditSteps

1. Consider the function below. f{\displaystyle f} is a twice-differentiable function of two variables x{\displaystyle x} and y.{\displaystyle y.} In this article, we wish to find the maximum and minimum values of f{\displaystyle f} on the domain |x|≤1, |y|≤2.{\displaystyle |x|\leq 1,\ |y|\leq 2.} This is a rectangular domain where the boundaries are inclusive to the domain.
• f(x,y)=x3+x2y−2y3+6y{\displaystyle f(x,y)=x^{3}+x^{2}y-2y^{3}+6y}
2. Calculate the gradient of f{\displaystyle f} and set each component to 0. Recall that in two dimensions, the gradient f=(∂f∂x,∂f∂y).{\displaystyle \nabla f=\left({\frac {\partial f}{\partial x}},{\frac {\partial f}{\partial y}}\right).}
• f∂x=3×2+2xy=0{\displaystyle {\frac {\partial f}{\partial x}}=3x^{2}+2xy=0}
• f∂y=x2−6y2+6=0{\displaystyle {\frac {\partial f}{\partial y}}=x^{2}-6y^{2}+6=0}
3. Solve for x{\displaystyle x} and y{\displaystyle y} to obtain the critical points. Generally, we will need to work with both components of the gradient to do this.
• Let’s start with the first component to find values of x.{\displaystyle x.} We can immediately factor out an x,{\displaystyle x,} which gets us x=0.{\displaystyle x=0.} The quantity in parentheses can also be 0, but that only gets x{\displaystyle x} in terms of y.{\displaystyle y.}
• 3×2+2xy=0x(3x+2y)=0x=0{\displaystyle {\begin{aligned}3x^{2}+2xy&=0\\x(3x+2y)&=0\\x&=0\end{aligned}}}
• 3x+2y=0x=−23y{\displaystyle {\begin{aligned}3&x+2y=0\\&x=-{\frac {2}{3}}y\end{aligned}}}
• Next, we move to the second component to find corresponding values of y{\displaystyle y} for the two values of x.{\displaystyle x.}
• x=0:{\displaystyle x=0:}
• 6=6y2y=±1{\displaystyle {\begin{aligned}6&=6y^{2}\\y&=\pm 1\end{aligned}}}
• x=−23y:{\displaystyle x=-{\frac {2}{3}}y:}
• 49y2−6y2+6=0(6−49)y2=6y2=2725y=±335{\displaystyle {\begin{aligned}{\frac {4}{9}}y^{2}-6y^{2}+6&=0\\\left(6-{\frac {4}{9}}\right)y^{2}&=6\\y^{2}&={\frac {27}{25}}\\y&=\pm {\frac {3{\sqrt {3}}}{5}}\end{aligned}}}
• We’ve found all possible values for y.{\displaystyle y.} Substituting y{\displaystyle y} only for the values that we got using the relation x=−23y,{\displaystyle x=-{\frac {2}{3}}y,} we obtain x=∓235{\displaystyle x=\mp {\frac {2{\sqrt {3}}}{5}}} (note the signs).
• Therefore, the four critical points are (0,±1), (∓235,±335).{\displaystyle (0,\pm 1),\ \left(\mp {\frac {2{\sqrt {3}}}{5}},\pm {\frac {3{\sqrt {3}}}{5}}\right).} These are only candidates for extrema, however.
4. Use the Hessian matrix to determine the characteristics of the critical points. This matrix is a square matrix of second derivatives. In two dimensions, the matrix is as below.
• H=(∂2f∂x2∂2f∂x∂y∂2f∂y∂x∂2f∂y2){\displaystyle H={\begin{pmatrix}{\dfrac {\partial ^{2}f}{\partial x^{2}}}&{\dfrac {\partial ^{2}f}{\partial x\partial y}}\\{\dfrac {\partial ^{2}f}{\partial y\partial x}}&{\dfrac {\partial ^{2}f}{\partial y^{2}}}\end{pmatrix}}}
5. Calculate second partial derivatives of f{\displaystyle f} and substitute the results into H{\displaystyle H}. Note that Clairaut’s theorem guarantees that mixed partials commute (for continuous functions), so in two dimensions, the off-diagonal elements of the Hessian are the same. See the tips for another reason why this must be true.
• 2f∂x2=6x+2y{\displaystyle {\frac {\partial ^{2}f}{\partial x^{2}}}=6x+2y}
• 2f∂x∂y=∂2f∂y∂x=2x{\displaystyle {\frac {\partial ^{2}f}{\partial x\partial y}}={\frac {\partial ^{2}f}{\partial y\partial x}}=2x}
• 2f∂y2=−12y{\displaystyle {\frac {\partial ^{2}f}{\partial y^{2}}}=-12y}
• H=(6x+2y2x2x−12y){\displaystyle H={\begin{pmatrix}6x+2y&2x\\2x&-12y\end{pmatrix}}}
6. Check the determinant of H{\displaystyle H}. If detH>0{\displaystyle \det H>0} (positive definite), then the point is either a maximum or a minimum. From an intuitive perspective, second partial derivatives of both components have the same sign. On the other hand, if detH<0{\displaystyle \det H<0} (negative definite), then the point is a saddle. Second partial derivatives of the components have opposite signs, so the point is not an extremum. Finally, if detH=0{\displaystyle \det H=0} (indefinite), then the second derivative test is inconclusive, and the point could be any of the three. See the tips for why this is the case.
• Let’s substitute in the (0,±1){\displaystyle (0,\pm 1)} critical points. Since we are only interested in the sign of the determinant, and not the values of the elements themselves, we can clearly see that both points results in a negative determinant. This means that (0,±1){\displaystyle (0,\pm 1)} are both saddle points. We do not need to go further for these two points.
• 200∓12|<0{\displaystyle {\begin{vmatrix}\pm 2&0\\0&\mp 12\end{vmatrix}}<0}
• Now let’s check the (∓235,±335){\displaystyle \left(\mp {\frac {2{\sqrt {3}}}{5}},\pm {\frac {3{\sqrt {3}}}{5}}\right)} points.
• |−635−435−435−3635|=35(216−16)>0{\displaystyle {\begin{aligned}{\begin{vmatrix}-{\frac {6{\sqrt {3}}}{5}}&-{\frac {4{\sqrt {3}}}{5}}\\-{\frac {4{\sqrt {3}}}{5}}&-{\frac {36{\sqrt {3}}}{5}}\end{vmatrix}}&={\frac {\sqrt {3}}{5}}(216-16)\\&>0\end{aligned}}}
• |6354354353635|=35(216−16)>0{\displaystyle {\begin{aligned}{\begin{vmatrix}{\frac {6{\sqrt {3}}}{5}}&{\frac {4{\sqrt {3}}}{5}}\\{\frac {4{\sqrt {3}}}{5}}&{\frac {36{\sqrt {3}}}{5}}\end{vmatrix}}&={\frac {\sqrt {3}}{5}}(216-16)\\&>0\end{aligned}}}
• Both of these points have positive Hessians.
7. Check the trace of H{\displaystyle H}. For candidate extrema, we still have to figure out whether the points are maxima or minima. In that case, we check the trace – the sum of the diagonal elements of H{\displaystyle H}. If tr⁡H>0,{\displaystyle \operatorname {tr} H>0,} then the point is a local minimum. If tr⁡H<0,{\displaystyle \operatorname {tr} H<0,} then the point is a local maximum.
• From above, we can clearly see that tr⁡H(−235,335)<0,{\displaystyle \operatorname {tr} H\left(-{\frac {2{\sqrt {3}}}{5}},{\frac {3{\sqrt {3}}}{5}}\right)<0,} and therefore, (−235,335){\displaystyle \left(-{\frac {2{\sqrt {3}}}{5}},{\frac {3{\sqrt {3}}}{5}}\right)} is a local maximum.
• Similarly, tr⁡H(235,−335)>0,{\displaystyle \operatorname {tr} H\left({\frac {2{\sqrt {3}}}{5}},-{\frac {3{\sqrt {3}}}{5}}\right)>0,} so (235,−335){\displaystyle \left({\frac {2{\sqrt {3}}}{5}},-{\frac {3{\sqrt {3}}}{5}}\right)} is a local minimum.
8. Check the boundaries if you are finding extrema in a closed domain. For open domains, this step is not needed. However, since our domain is closed, extrema can occur on the boundaries. Although this becomes a single-variable extrema test, it is a tedious process for even the simplest type of domain – a rectangular domain – and for more complex domains, it can get quite complicated. The reason is because we need to take four derivatives corresponding to each side of the rectangle, set all of them to 0, and solve for variables.
• Let’s check the right side of the rectangle first, corresponding to (1,y).{\displaystyle (1,y).}
• f(1,y)=−2y3+7y+1dfdy=−6y2+7=0{\displaystyle {\begin{aligned}f(1,y)&=-2y^{3}+7y+1\\{\frac {{\mathrm {d} }f}{{\mathrm {d} }y}}&=-6y^{2}+7=0\end{aligned}}}
• y=±76{\displaystyle y=\pm {\sqrt {\frac {7}{6}}}}
• The critical points are therefore (1,±76).{\displaystyle \left(1,\pm {\sqrt {\frac {7}{6}}}\right).} Doing single-variable second derivative tests on both of these points, we find that (1,76){\displaystyle \left(1,{\sqrt {\frac {7}{6}}}\right)} is a local maximum and (1,−76){\displaystyle \left(1,-{\sqrt {\frac {7}{6}}}\right)} is a local minimum.
• The other three sides are done in the same fashion. In doing so, we net the critical points below. Beware that you must discard all points found outside the domain.
• (0,2),{\displaystyle (0,2),} local minimum
• (−1,76),{\displaystyle \left(-1,{\sqrt {\frac {7}{6}}}\right),} local maximum
• (−1,−76),{\displaystyle \left(-1,-{\sqrt {\frac {7}{6}}}\right),} local minimum
• (0,−2),{\displaystyle (0,-2),} local maximum
9. Check the corners if you are finding global extrema in a closed domain. The four corners of the rectangular boundary must also be considered, just as how the two endpoints of a domain in single-variable calculus must be considered. Every extrema inside the domain and on the boundary of the domain, with the addition of the four corners, must be plugged into the function to determine global extrema. Below, we list the locations of the global maximum and minimum. They have values of f≈±6.041,{\displaystyle f\approx \pm 6.041,} respectively. Notice that neither of these global extrema were located inside the domain, but on the boundaries, which demonstrates the importance of identifying closed vs. open domains.
• Global maximum: (1,76){\displaystyle \left(1,{\sqrt {\frac {7}{6}}}\right)}
• Global minimum: (−1,−76){\displaystyle \left(-1,-{\sqrt {\frac {7}{6}}}\right)}
• Above is a visualization of the function that we were working with. We can clearly see the locations of the saddle points and the global extrema labeled in red, as well as the critical points inside the domain and on the boundaries.

## EditTips

• It is a good idea to use a computer algebra system like Mathematica to check your answers, as these problems, especially in three or more dimensions, can get a bit tedious.
• In step 5, we said that for continuous functions, the off-diagonal elements of the Hessian matrix must be the same. Not only is this shown from a calculus perspective via Clairaut’s theorem, but it is also shown from a linear algebra perspective.
• The Hessian is a Hermitian matrix – when dealing with real numbers, it is its own transpose. An important property of Hermitian matrices is that its eigenvalues must always be real. The eigenvectors of the Hessian are geometrically significant and tell us the direction of greatest and least curvature, while the eigenvalues associated with those eigenvectors are the magnitude of those curvatures. As such, the eigenvalues must be real for the geometrical perspective to have any meaning.
• When finding the properties of the critical points using the Hessian, we are really looking for the signage of the eigenvalues, since the product of the eigenvalues is the determinant and the sum of the eigenvalues is the trace. Oftentimes, problems like these will be simplified such that the off-diagonal elements are 0. Conducting the second partial derivative test will therefore be easier and clearer.
• In step 6, we said that if the determinant of the Hessian is 0, then the second partial derivative test is inconclusive. The reason why this is the case is because this test involves an approximation of the function with a second-order Taylor polynomial for any (x,y){\displaystyle (x,y)} sufficiently close enough to (x0,y0).{\displaystyle (x_{0},y_{0}).} This polynomial can be written in a quadratic form as below, where the matrix in the middle is the Hessian. Higher-order approximations must be used if the second partial derivative test is inconclusive, just like in single-variable calculus.
• 12(x−x0y−y0)(∂2f∂x2∂2f∂x∂y∂2f∂y∂x∂2f∂y2)(x−x0y−y0){\displaystyle {\frac {1}{2}}{\begin{pmatrix}x-x_{0}&y-y_{0}\end{pmatrix}}{\begin{pmatrix}{\dfrac {\partial ^{2}f}{\partial x^{2}}}&{\dfrac {\partial ^{2}f}{\partial x\partial y}}\\{\dfrac {\partial ^{2}f}{\partial y\partial x}}&{\dfrac {\partial ^{2}f}{\partial y^{2}}}\end{pmatrix}}{\begin{pmatrix}x-x_{0}\\y-y_{0}\end{pmatrix}}}
• Expanding out the quadratic form gives the two-dimensional generalization of the second-order Taylor polynomial for a single-variable function.

## How to Do Center Splits

The center splits is one of most impressive ways to showcase your flexibility. It involves extending the legs in opposite directions until they form a 180 degree angle, which is useful in array of physical activities, including gymnastics, martial arts and dance. The only way to achieve a complete center splits is through rigorous and repeated stretching. This article will show you some of the best exercises for increasing flexibility, along with some tips on how you can achieve center splits quickly and safely.

## EditSteps

### EditStretching Your Way to Splits

1. Do a butterfly stretch. The butterfly stretch is a great stretch for the center splits as it increases flexibility in the inner thighs, the groin and the hips. To perform:
• Sit on the floor and bend your knees until the soles of your feet are touching. Pull your heels as close towards your body as possible and use your elbows to push your knees towards the floor.
• Make sure to sit upright with your back straight. Hold the stretch for 30 to 60 seconds.
• To deepen the stretch, lean forward as far as you can and place your hands on the floor in front of your feet. Keep your back straight and your knees pressed to the floor.[1]
2. Do a pancake stretch. The pancake stretch is used by gymnasts to increase their flexibility and prepare for the center splits. To perform:
• Sit on the floor and spread your legs as wide as possible into a straddle position. Make sure that your legs are completely straight and that your toes are pointed.
• Keeping your back straight, lean forward as far as you can with your arms stretched out in front of you. Try to touch your chest to the floor, so your body is completely flat – just like a pancake!
• To deepen the stretch, try to grab your feet with your hands, while keeping the rest of your body flat to the ground. Hold the stretch for 30 seconds.[1]
3. Touch your toes. Touching your toes stretches your leg muscles and increases flexibility in the hamstrings, which is great for center splits. This stretch can be performed in a seated or standing position.
• To perform the stretch while standing, stand with your feet together and your legs straight. Reach down and attempt to touch your toes with your fingertips. Don’t bend your knees and try to place your weight on the balls of your feet, rather than your heels. Hold this stretch for 30 to 60 seconds.
• To perform the stretch while seated, sit with your legs stretched out straight in front of you and lean forward (keeping your back straight) until your touch your toes with your fingers. As you grow more flexible, try to grab the soles of your feet with your hands, in order to increase the stretch.[2]
4. Do a bent knees stretch. This stretch increases flexibility in the groin and hips. If you can perform it correctly, you are well on your way to achieving center splits.
• Kneel on the floor and place your hands on the ground in front of you for balance. Move your knees outwards – as far from your body as possible – until they form 90 degree angles. There should be a straight line running from one knee to the other.
• Move your weight from your hands to your elbows, to get deeper into the stretch. The goal is to get your hips flat on the ground, while maintaining the 90 degree angle with your knees. Once you have achieved the correct position, hold this stretch for 30 seconds.[1]
5. Do half squats. The half squat is a useful exercise for stretching the inner thighs. To perform:
• Hunker down into a low squatting position. Shift your weight onto your right leg and stretch your left leg straight out to the side, as if you were doing the center splits with that leg. Make sure to point your toes.
• Place your right hand on the floor (in front of your right leg) for balance and use your elbow to push the knees outwards until you feel a firm stretch in the inner thighs.
• Hold for 60 seconds, then repeat with the other leg.[3]
6. Do standing leg stretches. These simple leg stretches are essential when training to do the splits, as they increase flexibility in all of the necessary muscles. They are commonly used in martial arts training as preparation for the center splits.
• To begin, stand up straight and place your feet two shoulder widths apart. Bend forwards at the hips, keeping your legs completely straight. Let your body hang down and try to place your palms on the ground. As flexibility increases, try to get your elbows on the ground. Hold this stretch for 30 seconds.
• Next your can try ankle grabs. Lean to the right and grab the right ankle with both hands, then lean to the left and repeat with the left ankle. When holding these stretches, make sure that your hips are level rather than tilted to the side, otherwise the stretch will not be as effective.
• Next, try grabbing both ankles at the same time, bringing your chest as close to your knees as possible. Keep your back straight and relax your neck muscles so that your head is hanging straight down.
7. Practice your full center split. Of course, one of the best ways to achieve center splits is to practice doing center splits. The safest, most effective way to do this is as follows:
• Hunker down into a low squat and place both hands on the floor in front of you. Then, slowly begin to walk or slide both feet outwards, as far apart as you can manage.
• Your legs should be completely straight and your feet should be parallel as you lower yourself down into the stretch. Many people make the mistake of lowering themselves down by rolling back on their heels, but this will not provide as effective of a stretch and could cause injury. Your toes should only point outwards when you have achieved the full splits.
• Hold the stretch for as long as you can, then slowly come back into a squatting position to rest your muscles. When you feel ready, lower yourself back into the splits position again. Alternating between squatting and stretching will help you to get lower down each time you attempt the center splits.
• As you stretch, remember to keep your back straight and your hips in line with your legs. If your hips are too far forward or too far back, you will not be able to perform a center split correctly.
• The goal is to lower yourself down until your groin touches the floor. Once you have achieved this, you can try to roll your hips until you are sitting in an upright position, while maintaining a center splits.
• Remember to move slowly and breathe evenly. Do not push yourself too hard. You should feel a tight stretch in your inner thigh and groin muscles, but it should not feel painful. If you feel any discomfort or tearing sensations, come out of the stretch immediately.

### EditAchieving the Splits Quickly Yet Safely

1. Always warm up before you stretch. It is essential that you warm up before you stretch, in order to avoid injury and maximize your natural flexibility.
• Try doing jumping jacks or running on the spot for a few minutes before you begin your stretching routine.
• Alternatively, do your stretching at the end of a cardio workout . You will get the double benefit of increasing your flexibility while preventing muscle stiffness after your workout.
2. Stretch every day. Achieving the center splits requires a high level of flexibility, and flexibility is something that needs to be worked at consistently over time. In order to achieve the flexibility required for center splits, you need to be stretching every single day, or as close to it as possible.[4]
• Begin by stretching for 15 minutes a day, using a routine comprised of the stretching exercises outlined above. After a couple of weeks, increase the time spent stretching to 30 minutes a day, if possible. You can break this up into two 15 minute sessions a day.
• Remember that the more stretching you do, the faster you will achieve center splits.
3. Enlist the help of a friend. When stretching for the center splits, it can be very useful to enlist the help of a friend.
• Your friend can help by observing your posture, which can be difficult to correct by yourself. Ask them to make sure that your hips are in line and your shoulders are even. This is important as poor posture can affect the quality of your stretching and even cause injuries.
• A friend can also help you to deepen your splits by pushing down lightly on your shoulders or legs as you stretch. This can help you to get a fraction or two deeper into your stretch than you could on your own. Just make sure that they will respond quickly if you ask them to stop.
4. Wear socks. One simple tip that can help you to deepen your splits is to wear socks while you stretch, rather than stretching in your bare feet.
• The socks will allow your feet to slide easily along the ground, helping you to get deeper into the stretch. This is more effective on wooden floors than on carpet.
• However, make sure that you slide into the stretch in a careful and controlled fashion. Sliding too quickly may cause you to pull a muscle or tear ligaments.
• For safety, most of your body weight should be supported by your arms as you slide into a center split.
5. Find a practice space that works for you. When working towards the center splits, it is important that you find a suitable environment for stretching and practice. The type of environment that works best for you will depend on personal preference.
• Some people prefer to practice their center splits in a quiet, peaceful environment. They consider their stretching routine to be a type of meditation, where they can clear their mind and focus only on the sensations of their body.
• Other people find stretching a chore and need something to entertain themselves as they go through their routine. For example, some people like to watch television to distract themselves as they stretch.
6. Know your limits. The ability to perform the center splits is an impressive physical feat which requires discipline and perseverance to achieve. However, it is also important that you know your limits and refrain from pushing yourself past them in order to achieve your goal.
• Pushing yourself too hard will only result in injury, which could potentially prevent you from ever being able to do the splits.
• To safely yet effectively achieve the center splits, perform each stretch slowly and carefully, paying close attention to maintaining the correct posture. Listen to your body and you will soon achieve your goal!

## EditTips

• Always breathe out (exhale) while going into a split, this will help you get farther into your split.
• Be Patient. If you are a beginner and you don’t get it the first time, just keep on practicing.
• Remember that it takes months to accomplish this, not hours.
• You could also do wall splits. That is when you face the wall and stretch your legs out as if you we’re going to do a split. Go as far as you can until you feel a stretch in your legs.

## EditWarnings

• Don’t push yourself too far. This won’t help your splits. It will make your splits worse due to leg injury.
• Be aware that some body types will never be able to achieve full center splits, no matter how much stretching they do.

## EditSources and Citations

Cite error: <ref> tags exist, but no <references/> tag was found

## How to Build Love With Your Bearded Dragon

When you own a bearded dragon, it is natural to want to love your pet. Your dragon also can have affection for you if you take care of him. Learn how to hold him appropriately, bathe, and house him. By providing a good and safe home for your pet, you show your love.

## EditSteps

### EditProviding a Good Home

1. Purchase a high quality vivarium. A vivarium is a wooden tank with a glass front. It should have a tight lid and smooth sides to prevent the dragon from hurting his nose. Look for a vivarium that will be easy to clean. Vivariums should have a polyurethane or waterproof sealing. You should make sure the joints are caulked as well.[1]
• If you waterproof a vivarium yourself, be sure to allow the vivarium to dry for a week before putting your dragon in his home.[2]
• Make sure your dragon has enough space to run around, climb, and sit on branches.[3]
• Clean your pet’s habitat thoroughly regularly with a 10:1 mixture of water to bleach.[4] Remove any vegetables that he does not eat within four hours. Remove uneaten insects at the day’s end.[5]
2. Use an aquarium. You can also purchase an aquarium for your dragon. Baby dragons can live in a 10-15 gallon aquarium, while adults need a larger 55-60 gallon space.[6] Aquariums are a better short-term solution because it is difficult to regulate the temperature in them.[7]
3. Provide a vivarium and a heater. Wooden vivariums encapsulate heat better than glass or metal does. Aim to provide a less warm area (30 degrees Celsius/86 degrees Fahrenheit) and a warmer section (45 degrees Celsius/113 degrees Fahrenheit). The vivarium should be no smaller than 48 x 24 x 24 inches. Make sure your vivarium has air vents, minimally one per square foot. The vent should be on the upper part of the back wall rather than on the lower section.[8] See Care for Bearded Dragons for additional instructions on how to set up your pet’s habitat and vivarium.
• You can purchase a vivarium or make your own using DIY kits, such as Vivexotic.[9]
4. Install a good substrate. A substrate is the material that fills the bottom of the vivarium. Your pet will dig into the substrate.[10] Aim for a substrate that looks natural and makes your dragon feel at home. The substrate should also be absorbent. Because your dragon might eat parts of it unintentionally, try to find substrate that is non-toxic and safely digestible. You can utilize smooth newspapers, indoor or outdoor carpet, brown paper, or AstroTurf[11].
• Do not use wood chips or shavings, gravel, cat litter, or soil with pesticides, vermiculite, fertilizers, or surfactants for your substrate[12]
5. Provide appropriate furniture. Include branches for climbing. A reptile hammock is also fun for your pet and available at pet stores. Equip your dragon’s space with a “reptile hide,” which is an enclosed area in which your dragon can hide from you. Your dragon also will use this space for long periods of sleep. Place a “basking platform” in the habitat as well. This can be a rock or another surface within six to eight inches of the basking light source. Here a dragon can warm himself.[13]
• Be sure to strip all bark from natural wood branches so that your dragon does not eat the wood. Clean all branches prior to use.[14]

### EditHolding Your Bearded Dragon

1. Know good practices. Dragons actually like to be held. Wait three to four days after the dragon’s arrival to start holding him. Wash your hands before and after handling the pet. Begin by holding him for short periods multiple times a day. This helps build trust slowly.
• When holding your dragon, strive to have a quiet setting.[15]
• Babies, young children, women who are or might be pregnant, the elderly, or people with weakened immune systems should be careful about touching the dragon or being near its home.[16] Salmonella infections can occur.[17] Consult a doctor if you or your child belongs to one of these populations before allowing contact with the reptile.
• See Hold a Bearded Dragon for thorough tips.
2. Pick up the dragon. Gather your dragon from underneath his body in a slow, yet self-assured, scooping motion. Support his whole body plus his legs and tail.[18] Do not hold or pull your dragon by his tail. It can come off![19]
3. Calm your dragon. It is important to tame your dragon from the beginning. If your dragon appears aggressive (his “beard” will darken),[20] hold him tightly (not too tightly) with both of your hands and pet him. If your pet appears particularly agitated, release him for a short moment and then try holding him again until he calms himself. Training your dragon to be held and calm can take a number of months but it is vital to creating a good relationship with your dragon.[21]

### EditBonding With Your Dragon Through Care

1. Feed your dragon by hand. One way to bond with your dragon is to give him his food directly. You should do this occasionally but not so often that your dragon becomes reliant upon you. Instinctually, dragons hunt for their food so you should still give your dragon his food in a bowl most of the time. Place the food on the tip of your fingers. Your dragon will use his tongue to take the food from you. [22]
• Bearded dragons eat vegetables, living insects like crickets, waxworms, or mealworms, or bearded dragon foods available for purchase at pet shops.[23] Safe vegetables include squash, endive, turnip greens, or collard greens. Dragons also can eat apples, strawberries, and melons.[24]
• Do not feed your pet spinach, avocado, lettuce, or wild insects.[25]
• Implement a regular feeding plan. Whether feeding by hand or putting the food in your dragon’s home, your dragon will anticipate feeding time. He then will associate a positive experience with you![26]
• You should feed your young dragon once daily and your adults once per day or every second day.[27] Juvenile dragons require a mainly live food diet. Beardies are able to transition onto a vegetarian diet as they mature.
• It is possible your dragon might think your fingers are food. Be careful when feeding him![28]
2. Bathe your bearded dragon. By giving your lizard a bath, you will help him stay hydrated. Dragons absorb water through their pores. This is particularly important because dragons do not love to drink form a water bowl. To bathe your dragon, fill a sink, bathtub, or other clean container with warm water (try to reach 34.5-35.5 degrees Celsius/94-96 degrees Fahrenheit). Your dragon might enjoy this activity and again associate pleasure with you![29]
• Be sure to clean the bathing container thoroughly after use.[30]
• Mist your pet with water every second day. This will help your lizard also to stay hydrated.[31]
• Try to bathe your pet every four to eight days although you can bathe him every day.[32]
3. Aim for a stress-free environment. In order for your dragon to be happy, you should try to reduce his stress levels. High stress can lead to aggression. When your dragon sleeps, keep the noise levels in your house down. When your dragon decides to hide under something, this could signal that he wants to be alone. Try to respond appropriately to your dragon’s behavior and avoid disturbances unless there is a pressing need.[33]
• It’s okay to let your dragon roam a bit outside his habitat. Just be sure to keep him from the kitchen or other rooms where you eat or prepare food.[34]
4. Take your dragon to the veterinarian. Like any pet, bearded dragons should have yearly check-ups. Also, if you sense that your bearded dragon is acting differently than normal, schedule an appointment with the vet. Mites are a common issue that dragons face–they suck the reptile’s blood. Only a vet can determine, though, through testing whether your pet is truly ill.[35]

## EditSources and Citations

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## How to Do Internet Research

The internet has made researching a topic easier than ever before. Instead of making a trip to the library, people with internet access can simply pull up a search engine, type, and click away. But, in addition to making it easier to access information, the web has also made it easier to access misinformation.[1][2][3] However, by following some simple rules, you can avoid being fooled or misinformed by a phony, inaccurate, or biased web source.

## EditSteps

### EditKnowing Where to Begin

1. Decide where to start your search. If your employer, college, or university provides you with a search engine or directory, begin there. If you have access to a library database of research articles, such as EBSCOhost, start there.[4] Library databases provide you with access to peer-reviewed research, which is the gold standard for academic study. “Peer-reviewed” means that top experts in the field have reviewed the research to make sure it is accurate, trustworthy, and informed before publishing it. Even if you’re just trying to learn something for your own personal benefit, academic research will provide you with the most up-to-date, reliable information.
• You can usually access these databases through your home library’s website. Some academic and universities libraries may require a password if you are accessing them remotely (from somewhere other than in the library itself).
• If you don’t have access to a library, try using Google Scholar for your searches. You can find academic research through this search engine, and Google Scholar will show you where you can find free copies of the articles online.
2. Look for subject-specific databases. Depending on the area of your research, you have several options for online databases specific to your field. For example, if you are looking for research on education, the ERIC (Education Resources Information Center) is sponsored by the United States Department of Education and provides peer-reviewed research and informational materials on education topics.[5] If you’re looking for medical or scientific research, PubMed, sponsored by the United States National Library of Medicine, is a great place to start.[6]
3. Ask a librarian. If you have access to a library, make an appointment to speak with your reference librarian. These people are specially trained in helping you access the best research and knowledge available.[7] They can help you find sources and also help you determine whether sources are credible.
4. Use regular search engines with caution. Search engines crawl the web indexing pages by reading the words and phrases that appear on those pages. From there, the process is automated. Each search engine has an algorithm that’s used to rank results for specific searches. This means that no human is vetting the accuracy of the results. The “top” result is simply the result of an algorithm. It’s not an endorsement of the content or quality of the result.[8]
• Most search engines can be “gamed” by savvy websites in order to ensure their content comes up first. Moreover, each search engine has its own algorithm, and some tailor their results based on your browsing history. So the “top” result on Google will not necessarily be the “top” result on Yahoo, even with the exact same search phrasing.[9]
• Be aware that simply because you find information online doesn’t make it credible or authoritative. Anyone can make a webpage, and the amount of poor, unverified, and just plain wrong information often outweighs the good stuff online.[10] To help you sift through the useless stuff, talk to your teacher or librarian, and use library or academic search engines when possible.
5. Choose your keywords carefully. For any given inquiry, there are an almost limitless number of potential word and phrase choices you could enter into a search engine. Therefore, it’s important to think carefully about what you hope your search will find, as well as try multiple different search combinations.
• If you’re using an academic search engine, such as your library’s search feature, try using a combination of keywords and Boolean Operators, or words you can use to narrow down your search: AND, OR, and NOT.[11]
• For example, if you are doing research on feminism in China, you might run a search for “feminism AND China.” This will return results that include both of those topic keywords.
• You can use OR to run searches for related keywords. For example, you could search for “feminism OR feminist OR social justice.” This would return results that contain one or more of those terms.
• You can use NOT to exclude keywords from your search. For example, you could search for “feminism AND China NOT Japan.” You would not get any results that included Japan.
• You can use quote marks to search for full phrases. For example, if you want to search for academic performance, you would search for the whole phrase inside quotation marks: “academic performance.” Be aware, though, that using quotation marks will kick out any result that isn’t an exact match. For example, you would not get results about “school performance” or “academic functioning” because they are not worded exactly the way you searched.
• Use specific keyword phrases to locate the most relevant information. For example, if you are looking for information social welfare expenditures in the U.S., you’re more likely to get the results you want by searching for “total yearly amount spent on welfare programs in U.S.” than searching for “welfare,” which would bring up definitions of welfare, types of welfare in other countries, and thousands more results you don’t want. Be aware, though, that you can’t always find information like this — the more words you enter, the fewer results you’re likely to get.
• Use alternate words or keyword phrases to locate additional research sources. For example, if you are researching “welfare,” consider using “safety net” or “social programs” or “public assistance” in place of “welfare” to find different results. In many cases, your word choice might unintentionally bias your results, since terms like “welfare” are often politically loaded. Using a wider variety of terms ensures that you’ll be exposed to a broader — and therefore potentially less biased — set of sources.
6. Narrow when necessary. If you’re researching a topic about which you’re relatively uninformed, begin your search with broad terms, then use the information culled from that first search to begin narrowing your search.
• For example, in your search for “total yearly amount spent on welfare programs in U.S.,” you’ll quickly discover that there are several different public assistance programs, such as Temporary Assistance for Needy Families (TANF) and Supplemental Nutrition Assistance Program (SNAP). Use that information to decide which program(s) you’re interested in, and then perform a new (more specific) search, such as “total yearly SNAP expenditures in U.S.”

### EditGetting Good Sources

1. Look for credible, authoritative sources. Perhaps the most difficult — and important — task in internet research is ensuring the sources you select are credible. Generally, you want to prioritize information from government sources, academics, and nationally recognized news organizations.[12]
• Government sources will often have “.gov” somewhere in the webpage. For example, the United States Department of State’s website is www.state.gov. The official website for Australia’s Department of Defence is www.defence.gov.au.
• Websites that end in .edu belong to colleges and universities. However, you do need to be careful with .edu sites, because often faculty and students can run personal webpages that will have the .edu extension, but the information there may not be vetted by the university.[13] It’s better to find academic sources through an academic database or search engine, like EBSCOhost or Google Scholar.
• Websites that end in .org belong to non-profit organizations. While some of these are highly credible, some are not. Anyone can purchase a website with a .org extension. Check these sites carefully, and don’t rely on them as your sole source of information if you can avoid them.[14]
• Major news sources such as The Guardian, CNN, and Al Jazeera tend to be credible, but you also need to make sure you’re reading a factually based article and not an opinion piece. Many news sites also have blogs and editorial sites where people can state their opinions, which aren’t necessarily backed up by facts.
2. Cast a wide net. Don’t limit yourself to the first few results in the search engine. Look beyond the first page of search results to find information for your research.[15]
• While it’s impossible to view all of the results for most searches, it’s important to view at least several pages of results in order to ensure you’re not missing important information. Because of search engine optimization, if you’re using a regular search engine like Google or Yahoo, the first several pages might contain the links that were most effectively promoted, not the ones with the best information.[16]
3. Wikipedia can be a good place to start, but websites such as this are open to editing by anyone, which means that their information can be inaccurate, outdated, or biased.[17] If you want to use Wikipedia or another wiki for research, scroll down to the “References” section at the bottom of the page and check those out. Go to the original source whenever possible.
• For example, if you are writing a report on penguins, you could start with the Wikipedia page on Penguins. Scrolling to the References section would show you several peer-reviewed academic journal articles on penguins, along with references to book chapters by academic publishers. Look at those sources for more authoritative information.
4. Find the original source whenever possible. During your research, you will find many statements online, but not all of them are true or useful. Some sources will not cite any references, or they may twist the reference to say something other than what it originally stated. Don’t take anything at face value. Particularly when the website reporting a fact or statistic is questionable, you should attempt to find the original source.
• For example, if you’re doing research on changes in welfare expenditures during the past 20 years, there’s no reason to trust Yahoo answers, a blog, or any secondary source. Most credible sources will note that they’re using data from federal agencies. Therefore, it’s usually better to search for the original government data sources and cite them directly, rather than citing a page that is itself just reporting (possibly incorrectly) the data.
• Citing the original source will also make your own research more authoritative and credible. For example, it is much more impressive to your teacher if you cite an article from the National Institutes of Health (a US government source) than if you cite an article from webMD — even if they have the same information. If you can cite the original scholarly research that produced the information you’re discussing, that’s even better.
5. Look for consensus. If you can’t find the original source for a fact, your best bet is to verify the fact on multiple, credible sites.
• No matter what information you’re seeking, if you can’t find a single official source, it’s advisable not to trust a piece of information until you find identical information on several independent sites. So, for example, if you can’t find an original source for SNAP expenditures in 1980, enter the data you found into a search engine to ensure that the same number is reported on multiple sites and that those sites are not all citing the same (potentially erroneous) source.

### EditEvaluating for Credibility

1. Check the source’s affiliations.[18] Checking who owns or sponsors the website will help you figure out whether it is credible or not. For example, the Mayo Clinic website is owned by the Mayo Clinic, one of the most prestigious hospitals in the world. It is a not-for-profit organization, so it is not out to make money from its content. Its articles are written by medical professionals. These are good clues that information you find on this site will be credible. On the other hand, a “health” website that has a storefront or lots of ads, and doesn’t have any institutional or professional affiliations, won’t be as credible.
• If you’re using an academic database, check out who published the article or book. Texts from prestigious journals, such as the New England Journal of Medicine, and books from academic publishers like the Oxford University Press, carry more weight than sources from less-known publishers.
• If you’ve never heard of a source, the first place to look is the “About Us” (or similar) portion of the website. If that doesn’t provide you with a good idea of who’s producing the web page, try conducting an internet search for the site itself. Often news articles, Wikipedia entries, and the like that reference a source will include information about its affiliation(s), ideology, and funding. When all else fails, consider using a web domain search engine to discover who owns the website. However, if you’ve had to go to that length, chances are good that the site is too obscure to be trusted.
2. Check out the author. Unfortunately, many internet sources will not list an author. If you are searching online for peer-reviewed research, however, you will usually find sources with named authors. Look at their credentials.[19]
• For example, does this person have education in his/her field? Neil deGrasse Tyson has a Ph.D. in Astrophysics from the prestigious Columbia University, so it’s likely that what he says about astrophysics is credible and authoritative (meaning trustworthy and up-to-date).[20] On the other hand, an amateur star-watcher’s blog will not be authoritative, even if the information is accurate.
• Has the author written anything else on the topic? Many authors, including journalists and academic scholars, have areas of specialty and have spent years studying and writing about these topics. If the author has written many other articles on the same area, this makes him/her more credible (especially if those articles are peer-reviewed).
• If there is no author, is the source credible? Some sources, particularly government sources, will not list an author. However, if the source you are getting the information from is authoritative — such as an article on chickenpox from the Centers for Disease Control and Prevention — the absence of an author isn’t cause for concern on its own.
3. Look at the date. It’s important to make sure that your information is as up-to-date as possible, especially if you’re research a medical or scientific topic. Scientific consensus changes with the presence of new studies and information. Check when the article or website was published. Being more than five years old isn’t necessarily bad, but look for the most recent articles you can find for the best shot at updated information.[21]
• For example, if you were writing a research paper on treatments for cancer, you wouldn’t want to use only articles from the 1970s, even if they were published in prestigious academic journals.
4. Look for reliability and accuracy. There are many sources out there that claim to be fact-based but aren’t. Websites that appear to have a clear agenda are usually not good sources, because they may ignore or misrepresent evidence that disagrees with their position.
• Look for the site’s sources. A credible internet site will cite its sources. A really great site may even link out to the original research articles so you can track them down. If you can’t find any references for the information provided, or if the references are out of date or poor quality, it’s a good sign that your site isn’t reliable.
• Watch for bias. Highly emotional language, inflammatory rhetoric, and informal writing are all signs of potential bias in your source. Most academic writing tries to steer clear of these and aim for impartiality and objectivity as much as possible. If your website uses emotional language like “Manipulative big pharma companies are out to keep you broken and unhealthy to line their own pockets!” it’s a good sign that there is bias present.
• Review each website for grammatical errors and broken links. If the website is credible and reliable, grammar and spelling should be accurate and all links should take you to the appropriate landing page. Websites with numerous grammatical errors and broken links may be copying their information from another source or may not be legitimate.

### EditCompiling and Saving Your Sources

1. Cite your sources. In order to avoid the same errors made by inaccurate sites, you should always document your sources. This will allow you to return to them later, if necessary, and will allow others (when applicable) to verify your sources themselves.
• Bibliography entries for webpages traditionally consist of the author of the web article or webpage (if available), the title of the article or page, the name of the site, the site’s web address, and the date on which you accessed the article or page.
2. Beware of the ephemeral nature of the web. Just because a source is there today doesn’t mean it’s going to be there tomorrow. In order to guard against making your research irrelevant, consider your options for preserving web pages.
• The simplest way to save a webpage as you see it today is to print a hard copy or save it as a PDF.[22] This will allow you to refer back to the page, even if it’s moved or deleted.
• Since a hard copy or PDF version will only be available to you, you should periodically check the links in your research if it is published on the web. If you discover a web page has been deleted or moved, you can keyword search for its new location in a search engine or check to see if it was archived by Archive.org’s Wayback Machine, which preserves web pages as they previously displayed.[23]
3. Consider a technological fix. There are numerous free web browser features, apps, and services that can help you save your sources quickly and organize them easily.
• Using the bookmarks feature of your web browser is the simplest way to save sources. Rather than saving every source in the parent “Bookmarks” folder, consider creating subfolders for specific topics. For example, if you’re researching welfare, you might want to create a folder for “Welfare” in “Bookmarks” and then maybe even create more folders within “TANF,” “SNAP,” etc.
4. Build your own archive. Beyond simple bookmarking features and apps, more advanced research software and services can help you create your own personal repository of sources.
• Numerous services and apps have made it possible to sync sources to the cloud, capture images of web pages as they appear on the day you accessed them, add keywords to sources, etc.
• Many of these services, such as Zotero, are freeware created by academics and other open-source advocates. Others, such as Pocket, offer some services for free and charge for others. If you need functions beyond your web browser’s standard bookmarking features, consider using one of these sources to make organizing your sources easier.

## EditSources and Citations

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## How to Play Pool Like a Pro

To play pool like a pro, you need a good pool cue, a fluid stroke and precise aim. Whether you’re a casual pool player or you want to become accomplished, this article will give you the basic toolkit that you need to become better at billiards.

## EditSteps

### EditKeeping Proper Form

1. Check your hand position.
• Hold the thick end of the cue in your dominant hand with your palm facing upward. Find the spot on the wrap where the cue evenly balances. Grip your cue about 1″ behind that spot.
• Make a circle with the thumb and index finger of your non-dominant hand. Put the cue through the circle and rest it on the top of your middle finger, behind the knuckle. Spread out your “pinky”, ring and middle finger tips to create a tripod-like support.
• Place the ridge of your hand should on the table. Lift the other side of your hand a bit higher.
2. Assume the proper stance.
• Place the foot that is on the same side as your non-dominant hand in front.
• Position your other foot about 2 feet (60 cm) behind the front foot.
• Turn your body slightly away from the table so that it doesn’t interfere with the shot.
• Position yourself close to the table but not too close to the table. You want to lean into the shots a bit for more control.
• Proper form requires the cue stick to be directly below your chin during a stroke. If you compare the form of a professional pool player with that of a novice pool player, the professional player will always keep their head down also known as “being down on the ball” with the cue directly below his or her chin during the stroke.

### EditStriking the Ball

1. Chalk the cue tip before every shot as though you’re brushing the chalk on with a paintbrush. Avoid twisting the chalk on top of the cue.
2. Hold your cue parallel to the table for maximum control.
3. Accelerate gradually as you approach the ball. Imagine that you are moving your arm through the water in a swimming pool instead of hitting the ball with a quick strike. A longer stroke imparts more momentum to the ball.
4. Keep your follow-through straight and relaxed. The cue should continue on its course and almost hit the table ahead of the ball’s starting position. Your cue shouldn’t slow down until the tip has actually hit the ball.
5. Stay down after the shot. This position allows you to analyze the angle of the ball and the direction of every other ball that it strikes. It also ensures that you don’t cause the shot to deviate by accidentally introducing a jumpy motion.
6. Practice your stroke without actually striking balls until it feels comfortable.

### EditPerfecting Your Aim

1. Imagine an invisible ball next to the ball that you want to sink into the pocket.
2. Place your cue above the target. Angle the cue so that it creates a parallel line from right above the cue ball to the target.
3. Back your cue up and place the tip on the table where the center of the invisible ball (the one you imagined next to the real ball) would be. Maintain the angle that you just made when you lined up the ball and the pocket.
4. Keep the cue tip on the table. Pull the rest of the cue around to the right or left until the cue is positioned over the white ball. You now have the angle at which you need to hit the white ball to sink the other ball.
5. Set your shot up at the angle you just calculated. Strike the center of the white ball so that it makes contact with the other ball.
6. Start playing with your non-dominant hand all the time until a little after the time you become ambidextrous. It will make you less likely to win the current game but more likely to win future games. Sometimes in pool, you get a shot that would be an awkward angle with your dominant hand, but your non-dominant hand will gain skill faster for those awkward shots if you play with your non-dominant hand all the time than if you just do it for those shots. In fact, skill transfers somewhat from one task to another task to your non-dominant hand will gain skill for pool faster if you you do everything with your non-dominant hand than if you just play pool with your non-dominant hand like in other activities.

### EditChoosing a Good Pool Cue

1. Feel the wrap or butt of the cue.
• Choose a larger wrap if you have large hands and a smaller wrap if you have small hands. The most important point is to find a wrap that feels good in your hands.
• If your hands sweat, choose a cue wrapped in Irish linen for absorption. Otherwise, choose a leather wrap or a cue with no wrap.
2. Check the shaft. Most shafts have a diameter of 12mm to 13mm. While 13mm is the most commonly selected size, a smaller shaft can make the bridge position more comfortable for people with smaller hands.
3. Measure the pro taper. The shaft maintains its diameter for 10″ to 15″ before it starts to taper toward the cue. A shorter taper gives you a firmer hit.
4. Know the cue weight. Most players choose a weight between 19 and 20 ounces.
5. Check cue length. Most cues are 57″ or 58″ long, but you can special order different lengths.
6. Pick your cue tip. Cue tips are made of leather and generally rated medium to hard. A tip that will wear well gives you better control of the ball.
7. Make sure no parts are loose. Any loose parts will absorb the energy from your shots and will hamper your ability to strike the ball well.

## EditTips

• Don’t defeat yourself. Technique is important, but your main job is to stay calm and mentally focused.
• Find an instructor and work out your basic technique. Sound advice at early stage can help you avoid the frustration and enjoy the game more. In addition, you’ll avoid having to correct bad habits developed over your pool career.

## EditWarnings

• Many house cues are damaged or warped due to cheap materials and excessive use.
• Avoid betting with strangers. Strangers may “hustle” you by appearing to be bad pool players. However, after they place a bet with you, they suddenly develop excellent pool skills so that you lose the bet.

## EditThings You’ll Need

• Pool cue
• Pool table
• Billiard balls
• Chalk

## How to React During an Earthquake

Earthquakes happen when the earth’s crust shifts, causing seismic waves to quake and crash up against one another. Unlike hurricanes or floods, earthquakes come without warning and are usually followed by similar aftershocks, although the aftershocks are usually less powerful than the quake. If you find yourself in the middle of an earthquake, there’s often only a split-second to decide what to do. Studying the following advice could be the difference between life and death.

## EditSteps

### EditDrop, Cover and Hold On (Indoors)

1. Drop to the ground. The drop, cover, and hold on technique is the cousin of the famous “stop, drop and roll” for fires. While it’s not the only method of protecting yourself indoors during an earthquake, it is the preferred method of the Federal Emergency Management Agency (FEMA) and the American Red Cross.[1]
• Big earthquakes occur without much, if any, warning, so it’s recommended that you drop to the floor as soon as it hits. A small earthquake could turn into a big earthquake in a split-second; it’s better to be safe than sorry.
2. Take cover. Get under a sturdy table or other piece of furniture. If possible, stay away from glass, windows, outside doors and walls, and anything that could fall, such as lighting fixtures or furniture. If there isn’t a table or desk near you, cover your face and head with your arms and crouch in an inside corner of the building.
• Do not:
• Run outside. You’re more likely to get injured trying to get out of the building than staying put.[2]
• Head for a doorway. Hiding under a doorway is a myth.[3] You’re safer under a table than you are under a doorway, especially in modern houses.
• Run to another room to get under a table or other piece of furniture.
3. Hold on. The ground may be shaking and debris could be falling. Hold on to whatever surface or platform you’ve gotten under and wait for the shaking to subside. If you were unable to find a surface to hide under, continue to keep your head shielded by your arms and tucked down low.
4. If you find yourself in bed while an earthquake strikes, stay there. Hold on and protect your head with a pillow, unless you are under a heavy light fixture that could fall. In that case, move to the nearest safe place.
• Many injuries are caused when people leave their bed and walk across broken glass with their bare feet.[4]
5. Stay inside until shaking stops and it is safe to go outside. Research suggests that many injuries occur when people inside buildings attempt to move to a different location inside the building or try to leave.
• Be careful when you do go outside. Walk, do not run, in case of violent aftershocks. Collect yourself in an area without wires, buildings, or crevasses in the earth.
• Do not use elevators for egress. The power can go out, causing you to be trapped. Your best bet is to use the stairwell if it’s free.

### EditTriangle of Life (Indoors)

1. Use the triangle of life method as an alternative to drop, cover, and hold on. If you can’t find a desk or a table to duck under, you have options. Although this method is disputed[5][6][7] by many of the world’s leading earthquake safety officials, it could save your life in the event that a building you’re in collapses.
2. Find a structure or piece of furniture nearby. The triangle of life theory is that people who find shelter near, not under, household items such as sofas are often protected by voids or spaces created by a pancake collapse. Theoretically, a collapsing building would fall on top of a sofa or desk, crushing it but leaving a void nearby. Devotees of this theory suggest that sheltering in this void is the safest bet for earthquake survivors.
3. Huddle in the fetal position next to the structure or piece of furniture. Doug Copp, the main proponent and proponent of the triangle of life theory, says that this safety technique is natural for dogs and cats and can work for you, too.
4. Consider this list of what not to do in the event of an earthquake. If you can’t find a safe place to duck nearby, cover your head and get into the fetal position wherever you are.
• Do not:
• Go under a doorway. People under doorways are commonly crushed to death if the door jamb falls under the weight of the earthquake’s impact.
• Go upstairs to get under a piece of furniture. Stairs and staircases are dangerous places to tread during an earthquake.
5. Know that the triangle of life method is not supported by scientific findings and/or expert consensus. The triangle of life technique is controversial. If you find yourself with several options about how to proceed during an earthquake indoors, attempt the drop, cover, and hold technique.
• There are several problems with the triangle of life technique. First, it’s difficult to know where triangles of life form, since objects in a quake move up and down as well as laterally.
• Second, scientific studies tell us that most deaths in earthquakes are linked to falling debris and objects, not falling structures.[8] The triangle of life is predominantly based on earthquakes that cause structures, not objects, to fall.
• Many scientists believe that it’s also more likely to sustain injuries trying to move somewhere instead of staying put.[9] The triangle of life theory advocates moving to safe areas over staying put.

### EditSurviving Earthquakes Outdoors

1. Stay outdoors until the shaking stops. Do not try to heroically rescue someone or venture indoors. Your best bet is to stay outside, where the risk of collapsing structures is diminished. The greatest danger exists directly outside buildings, at exits, and alongside exterior walls.
2. Stay away from buildings, street lights, and utility wires. These are the main risks of being outdoors when an earthquake or one of its aftershocks is in progress.
3. If in a vehicle, stop as quickly as possible and stay in the vehicle. Avoid stopping near or under buildings, trees, overpasses, and utility wires. Proceed cautiously once the earthquake has stopped. Avoid roads, bridges, or ramps that might have been damaged by the earthquake.[10]
4. If trapped under debris, stay calm and take preventative measures. Although it may seem counterintuitive, waiting for help is probably your best bet if you find yourself trapped under immovable debris.
• Do not light a match or a lighter. Leaking gas or other flammable chemicals may accidentally light on fire.
• Do not move about or kick up dust. Cover your mouth with a handkerchief or clothing.
• Tap on a pipe or wall so rescuers can locate you. Use a whistle if one is available. Shout only as a last resort. Shouting can cause you to inhale dangerous amounts of dust.
5. If you are near a big body of water, be prepared to face a possible tsunami. A tsunami happens when an earthquake causes an extreme underwater disturbance, sending powerful waves towards shores and human habitation. If there’s just been an earthquake and its epicenter is in the ocean, there’s a good chance you’ll have to be on the lookout for tsunamis.

## EditWarnings

• Be aware that some earthquakes are actually foreshocks and a larger earthquake might occur.

## EditSources and Citations

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