Solve sin^2x - 2sinx - 3 = 0 on the interval xE [0, 2pie]

Answer 1

pi, not pie

sin^2x - 2sinx - 3 = 0
(sinx-3)(sinx+1) = 0
sinx=3 nope
sinx = -1
x = 3pi/2

Answer 2

4cos2x - cosx-3 =0

0 to 2pi