I've been taking lessons out of this Calc book I picked up (Thomas-Finney 9th Edition), and I've been doing decently. But I've come across these sets of problems that I just can't for the life of me figure out, since the book doesn't give any examples similar to them.

If anyone could help, I'd be very, very, very grateful. If possible, a detailed explanation would be great!

Find the derivative of the function:

y = x^2sin^4x + xcos^-2x (Note: It's the sine of x to the fourth power, just for clarification. Same with the cosine section.)

and..

y = 4/3[pi] sin3t + 4/5[pi] cos5t

By [pi] I mean 3.14...