How do you find the integral of cos(x)/(5+sin^2(x))dx?

1 Answer
Mar 10, 2018

Given: int cos(x)/(5+sin^2(x))dx

Let u = sin(x), then du = cos(x)dx):

int cos(x)/(5+sin^2(x))dx = int 1/(5+u^2)du

You should recognize the right side as the inverse tangent form:

int cos(x)/(5+sin^2(x))dx = sqrt5/5tan^-1(u/sqrt5)+ C

Reverse the substitution for u:

int cos(x)/(5+sin^2(x))dx = sqrt5/5tan^-1(sin(x)/sqrt5)+ C