Thread: Intigrating this seemingly simple expression

I know that the antiderivative is cos^2(x) is (x+cos(x)sin(x))/2, but how the heck can you derive it?

Originally Posted by jagged

I know that the antiderivative is cos^2(x) is (x+cos(x)sin(x))/2, but how the heck can you derive it?

Make the appropriate substitution suggested by the double angle formula:

.

Then, after integrating, make the substitution in your answer.

thanks... ive forgotten basic methods of integration since spring break