Find
You know how to find the derivatives of and don't you? It's pretty easy if you know the derivatives of sine and cosine, so I won't go through it, I'll just write them down:
So to find , just apply the quotient rule.
EDIT: The last line is WRONG. I didn't use the distributive property on the first term. When I mulitplied by I should have obtained .
Ohh... I think I understand what you did :33
But I have the answer to the question && it doesn't match up.
The problem is that I can't get from the quotient rule step to the answer.
Sorry for complicating it so much >_<
The Answer: