Hi!

I've got a little problem solving this:

f(x)=tan^3(4x+x^2)

(its a cubed tangent..)

Can't find f' ...

well I do get f'(x)=3.tan^2(4x+x^2)*(2x+4)*(1+tan(4x+x^2))

But it dosent sound right to me so have you got any idea whats wrong and how to solve this?

Thank you

charlie