1. ## simplifying

I want to simplify the expression to the expression given by Wolfram. It does not give the steps. Can I have a hint?

2. ## Re: simplifying

Originally Posted by Stuck Man
I want to simplify the expression to the expression given by Wolfram. It does not give the steps. Can I have a hint?
Posting both the original expression and Wolfram's attempt would be a good start

3. ## Re: simplifying

Are you having a laugh? It's this:

$\frac{(2cosx+cos2x)(2cosx+2cos2x)-(2sinx+sin2x)(-2sinx-2sin2x)}{(2cosx+cos2x)^2+(2sinx+sin2x)^2}$? I can't see a fast approach, but I assume there must be one.

4. ## Re: simplifying

The question is "Express the derivative of arctan((2sinx+sin2x)/(2cosx+cos2x)) in terms of cos x."

5. ## Re: simplifying

Honestly, I'm struggling to find a shortcut. Expanding and simplifying the brackets reduces the number of terms, but it's a complete mess.