tan3x (tanx - 1) = 0

=> tan3x = 0 or tanx - 1 = 0

=> 3x = arctan0

=> x = (1/3)arctan0

=> x = k*pi for k an integer

=> tanx = 1

=> x = arctan(1)

=> x = pi/4 + k*pi for k an integer

are these 2's supposed to be squares?

Find all solutions of the equation in the interval [0, 2π)

2. 2sin2= 2 + cosx

3. 2sin2x + 3sinx + 1 = 0