Exercise #17 notes
- 1. Exercise #17 Sum and Difference Identities II Express cos x as a function of x only. 2 Therefore, we can use the sum and difference identities when proving identities. Example 1 3 Prove sin x sin x cos x . 3 2 2 Working Backwards Evaluate without using a calculator: 5 5 sin cos cos sin 9 36 9 36
- 2. Try Find the exact value of: cos cos sin sin 12 3 12 3 Example Prove that sin( ) sin( ) 2cos sin . Journal 4 5 3 Given that tan where is not in quadrant IV and cot where , 3 12 2 find cos( ) .