Find cos 2y + Questions on Double & Half Angles.?

1.) If cos y = 1/2, and 3π/2 %26lt; y %26lt; 2π, find cos 2y





2.) If tan B = 4/3, and B lies in Quadrant III, find sin(B/2)





3.) The Expression 2sinx cosx is equivalent to which of the following:


a. 2sinx


b. sin 2x


c. cos 2x


d. tan 2x





4.)The expression 2cos^2(15°)-1 has the same value as:


a. sin 15°


b. cos 15°


c. sin 30°


d. cos 30°





5. If siny = -(7/25), find cos 2y





6. If sin B = 0.6, and B terminates in Quadrant II, find cos (B/2)





7. If cos A = -(5/13) and π %26lt; A %26lt; 3π/2, find cos(1/2)A

Find cos 2y + Questions on Double %26amp; Half Angles.?
1. cos 120 which is equal to 2pi/3


2


3. sin2x


4. cos30


thats all i kno rite now sry