Proving+Trigonometric+Identities

__** Learn How To Do It **__
-Simplify one or both sides of an equation so that they are equal. -When solving DO NOT cross over the equal sign. -Know the fundamental Pythagorean identities.
 * To prove a trigonometric identity,**

1. Try to stay on one side, and start with the side that has addition or subtraction. 2. Simplify terms as much as possible. Look out for: 3. Change trig functions to Sin and Cos.
 * There are many different approaches one can take when solving such problems, to use the shortest method possible keep these things in mind:**
 * fractions or like terms that can be combined
 * anything that can be factored in order to simply the expression (difference of two terms or perfect square trinomials.
 * denominators that can be mulitipied by the conjugate
 * Algebreic expressions that can be distributed, squared or multiplied.

** __Some Examples Of Proofs:__ **
__Proof:__ cscx = cotx/cosx


 * __Step 1:__ Equation becomes: cscx = cosx/cosxsinx**
 * The cot(x) was changed to cos(x) over sin(x)
 * __Step 2:__ Equation becomes: cscx = 1/sinx**
 * Cos(x) over Cos(x) cancle and change to just one.
 * __Step 3:__ Equation becomes: cscx = cscx**
 * One over Sin(x) is the same as Csc(x)

media type="custom" key="5850711"media type="youtube" key="9uoKutwuCio" height="385" width="480"
 * __//ALWAYS write out the entire equation for each step of the process//__**

__ Let's Practice __ __ Let's Review __

media type="youtube" key="pviWtesNnAY" height="385" width="480" media type="youtube" key="OJz-fOzFbEc" height="385" width="480" The video below is a different way to prove a trigonometric identity, but it still works. It's an interesting way to look at proving identities! media type="youtube" key="4W2KuIZm2c8" height="385" width="480" //and// [] Use this link for more practice: []