I'm asked to evaluate the definite integral of the square root of 1+cos(4x)dx from 0 to pi/4. I don't even know which method would be best to use here, so essentially I don't even know how to start this problem! Could somebody help me out?
I saw in the original problem that it had . This looked similar to if we take . This now looks similar to the half angle equation for cosine, which is . All I need to do with is to get a two in the denominator. Multiplying by allows me to do this, since . Now I can apply the identity to get where we said .
Does this clarify things?