Please I really need help with this hw question Prove without trig identity that f`(x)=0 for F(x)=Asin^2(Bx+C)+Acos^2(Bx+C)
You're not supposed to use the obvious identity that simplifies this? I suppose you could just use the derivatives of sin and cos along with the chain rule to directly compute the derivative. But eventually you'll need to simplify using some trig identity.
Are you sure? I was able to get F'(x) = 0 by using the chain rule, and yet I didn't use any trig identity.
It's really simple - just use chain rule to take the d/dx of the whole expression. No trig or any other kinds of tricks necessary. Are you familiar with the use of chain rule?