It's been a while since my last math class, and my current teacher isnt the greatest. We're assigned a fair amount of homework everynight, and it just takes me forever to do it, and its taking all of my time, leaving no time left for other classes. I have some problems and if anyone can help me with them, I'd greatly appreciate it. I learn best by seeing an example, but our teacher tends not to give many examples, if any.

2)If sin x = −3/5,x in quadrant III, then what are the following ?

sin2x

cos2x

tan2x

4)If sin4 x = A+Bcos2x+Ccos4x, then what are A, B, C ?

5If sin(15Degrees) = 1/2 sqrt(A - sqrt(B))

B, then, by using a half-angle formula, find A , B

I have some more, but help with these would be amazing.