sin θ = 0

The general solution of sin θ = 0 is given by

θ = nπ, n ∈ Z where Z is the set of all integers.

cos θ = 0

The general solution of cos θ = 0 is given by

θ = (2n+1)π/2, n ∈ Z.

tan θ = 0

The general solution of tan θ = 0 is given by

θ = nπ, n ∈ Z