If f(x)=4sinx/1+cosx

Question

then f'(x)=_____?

I think that the derivative of 4sinx would be 4cos and cosx would be sinx but I don't know where to go from there.

Answer 1

put u=4sin(x), and v=(1+cos(x)),

then use the quotient rule:

d(u/v)= (v du/dx - u dv/dx) / v²

Answer 2

Sorry, I didn't see the comment the first time,
d(cos(x))/dx = -sin(x)