7 ...and using double angle formulas again you get that ..you can take it from there
I have 7 problems that I need help with. If you know just one, it would be EXTREMELY helpful!
1. Find all solutions to csc x= -1.15 in the interval 0<x<2pi.
2. Solve 15cos^2(x) - 7cosx-4=0 by factoring and find solutions in 0<x<2pi.
3. Use appropriate addition formula to simplify cos(A-B) given sec(A) = -2/√3 where 90°<A<180° and tan(B) = 1/4 where 0°<B<90°
4. Find all solutions of 2sin^2(x) - 9sin(x)+4=0. Express in radians
5. Find all solutions to sin(3x) = -√2/(2) in interval 0<x<2pi.
6. Find all solutions for 2sin(x) = √2cos(2x) in interval 0<x<2pi.
7. Verify the following identity: cos(4x) = 8cos^4(x) - 8cos^2(x) + 1.