These are 3 questions, please make it clear and thank you

Question 1: Exit Fullscreen Use an appropriate compound angle formula to determine an exact value for each of the following: 7 7 a) Cos 12 b) sin 11 7 12 Prove that sin (2nt - x) = -sinx. c) sin 12 -!- Prove that secx = 2(cos.x sin 2x - sinxcos 2x) sin 2x d) cos (- 12 Question 2: Express cos as a trigonometric function of an angle in quadrant