I am having a hard time doing this.

Use substitution and the results you established to evaluate the integral:

the integral is sin(2x) / (2 + cos(x))

The results I established are :

cos(x) = (1 - t^2) / (1 + t^2)

sin (x) = 2t / (1 + t^2)

dx = (2 / (1+ t^2)) dt

Help please!