问题 填空题
化简:
cos(θ+
π
2
)sin(θ+3π)
sin(θ-
π
2
)cos(θ-2π)tan(θ+π)
=______.
答案

cos(θ+
π
2
)sin(θ+3π)
sin(θ-
π
2
)cos(θ-2π)tan(θ+π)
=
sinθsinθ
-cosθcosθtanθ
=
sinθsinθcosθ
-cosθcosθsinθ
=-tanθ.

故答案为:-tanθ.

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