1. The problem statement, all variables and given/known data take the wronskian of [cos(theta)]^2 and 1+cos(2theta) 2. Relevant equations 3. The attempt at a solution so I set up the determinant [cos(theta)]^2 1+cos(2theta) as my y1 and y2 respectively and -2cos(theta)sin(theta) and -sin(2theta) as my y1 and y2 prime respectively i get my determinant to be -2cos(theta)sin(theta)*[cos(theta)]^2 +2cos(theta)sin(theta)*(1+cos(2theta)) the answer in the back says it should be 0. So I'm assuming I have to do something with basic trig identities to get it to 0? I can't seem to get it to go to 0 though I've been trying for 30 minutes :(. Can anyone offer some insight?