Here's a really basic intro to some trigonometric identities. If you're struggling with the practice problems, you can refer to this video for some help.

This is an easy to follow and simple video that covers basic problems to help you learn and further understand trigonometry identities.

Practice Problems & Solutions: To view the answers, simply highlight the space to the right of the bubbles! There are also multiple ways to solve the same problem! Do not be discouraged if you did not solve it in the same manner. As long as all of the steps that you did are mathematically correct, it is still okay as you are ultimately arriving at the same answer. That's the beauty of proofs as you are allowed to think differently :).

This is an easy to follow and simple video that covers basic problems to help you learn and further understand trigonometry identities.

Practice Problems & Solutions:

To view the answers, simply highlight the space to the right of the bubbles!There are also multiple ways to solve the same problem! Do not be discouraged if you did not solve it in the same manner. As long as all of the steps that you did are mathematically correct, it is still okay as you are ultimately arriving at the same answer. That's the beauty of proofs as you are allowed to think differently :).- sec4A - sec4Asin4A - 2tan2A = 1
- sec4A - sin4A/cos4A - 2tan2A = 1
- sec4A - tan4A - 2tan2A = 1
- (sec2A)2 - (tan2A)2- 2tan2A = 1
- (sec2A+tan2A)(sec2A - tan2A) - 2tan2A = 1
- (sec2A+tan2A)(1) - 2tan2A = 1
- sec2A + tan2A - 2tan2A = 1
- sec2A - tan2A = 1
- 1 = 1

6. sin2x * tan2x + cos2x * cot2x = tan2x + cot2x - 17.)Verify the identity cos x * tan x = sin x

(highlight for answer!)cos x * tan x = cos x * (sin x / cos x) = sin x

8.)Verify the identity cot x * sec x * sin x = 1(highlight for answer!)cot x * sec x * sin x = (cos x / sin x) * (1/ cos x) * sin x

(cos x / sin x) * (1/ cos x) * sin x = 1

If you need more practice in finding the sum of trigonometic functions or need to relearn a few things, go to http://www.mathcentre.ac.uk/resources/uploaded/mc-ty-rcostheta-alpha-2009-1.pdf.