sin(θ-π)=sin[-(π-θ)]=-sin[π-θ]=-sinθ
cos(θ-3π/2)=cos(3π/2-θ)=-sinθ
cot(-θ-π)=-cot(π+θ)=-cotθ
tan(θ+5π)=tan(π+θ)=tanθ
sec(-θ-2π)=sec[-(2π+θ)]=secθ
csc(π/2-θ)=secθ
原式=-sinθ*(-sinθ)*(-cotθ)
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tanθ*secθ*secθ
=sin^2θ*cos^2θ*(-cot^2θ)
=-sin^4θ