Question

1)ctg3x=-1 2) 1/3sin 3x-1/3=0

Answer 1

1)  ctg(3x) = - 1
3x = -π/4 + πn, n∈Z
x = (-π)/12 + (πn)/3, n∈Z

2)  1/3sin 3x - 1/3 = 0
1/3sin 3x = 1/3
sin3x = 1
3x = π/2 + 2πk, k∈Z
x = π/6 + (2πk)/3, k∈Z