1) ctg(4x) = -1 4x = 3π/4 + πk x = 3π/16 + πk/4 2) 3sin^2(x/2) - 2sin(x/2) = 0 sin(x/2) * (3sin(x/2) - 2) = 0 a) sin(x/2) = 0, (x/2) = πk, x = 2πk b) sin(x/2) = 2/3, (x/2) = (-1)^k * (arcsin(2/3)) + 2πk