1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution So I am tasked with answer #3 and #4. I have supplied the indicated parenthesis of 8 also with the image. Here is my thinking: Take the fourier series for |sin(θ)|. Let θ = 0 and we see a perfect relationship. sin(0) = 0 and cos(0) = 1. So with just a little algebra and setting sin(θ) = the fourier series of sin(θ) We can easily show #3 part 1. Similiarly, with setting θ = pi/2 we can solve for #3 part b. Is this the correct way of going about this? I ask this question, even tho I have perfect results, as this seems too simple and I feel like I haven't used anything here. Is this really what the question is asking?