1. The problem statement, all variables and given/known data All solutions in the interval 0 ≤ x < 2∏ Sin 2x = -2cos x 3. The attempt at a solution I went about it in two different ways. The first way: I simply used the double angle formula to get 2sinx cosx + 2cos x = 0 From this we get that whatever makes cos x = 0 will make the whole equation 0. There are two answers within the interval; ∏/2 and 3∏/2. This is the correct solution. When I was studying for my midterm I went about it in a different way though, and I only got one solution. I was wondering what I was doing wrong as it seems to be all legal algebra to me. 2sinx cosx = -2 cos x divide both sides by cos x 2sinx = -2 divide by 2 sin x = -1 This only gives me one solution, 3∏/2. What am I doing wrong?