Please Help Me Double Check this Derivative (dy/dx) Problem?

[nuvydeep]

Hello folks,

I took a picture of my work.

Tell me if the method I am using is correct? Thanks!

This is the problem:

This is my work: (
http://img413.imageshack.us/img413/7016/0531001531.jpg)

Goto the link to see full sized pic because the thread cuts it off: http://img413.imageshack.us/img413/7016/0531001531.jpg

 

[wjm11]

Looks okay to me. You had the derivative done in the first line. All the rest were just trig manipulations. Any directions for what final form you are supposed to put the answer in?