Question

solve the given equation


cos(θ) − sin(θ) = 1

Answer 1

If theta is zero then cos(θ) is one and sin(θ)is zero

Answer 2

what about when sin=-1 and cos=0?

to make sure, let's work it out.
Note that cos π/4 = sin π/4 = 1/√2

cosθ - sinθ
1/√2 cosθ - 1/√2 sinθ = 1/√2
cos(θ+π/4) = 1/√2
θ+π/4 = π/4 or 7π/4
θ = 0 or 3π/2