hey, just need some help on my homework.

First, how would I make a table for a graph of the equationy = -2sin2x. I used 0, pi/2, pi, 3pi/2, 2pi as the x values, but everything equals 0

Second, I have a sheet that says the formulas for double angles, half angles, difference of two angles, etc. nothing with tan though. how would i answer the question "If A and B are acute angles such thatcos A = 24/25andtan B = 15/8, find the exact value ofsin(A - B)"

Last question. This one has tan too. the question is "The Double Angle formula for the tangent is:tan2x = (2tanx)/(1-tan^2x). Derive this formula from the formulas forsin2xandcos2x"