(1) tan(-θ)*sin(π/2-θ)+cos(3π/2+θ)=-tan(θ)*cos(θ)+sin(θ)=-sin(θ)+sin(θ)=0
(2) tan(2π+θ)*tan(5π/2-θ)=tan(θ)*tan(2π+π/2-θ)=tan(θ)/tan(θ)=1