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