θ属于(π/2,π),则根号下1-2sinπ+θsin(3π/2-θ)=?
1个回答
θ属于(π/2,π),则
sinθ>0 cosθ0
原式
=√[1+2sinθ(-cosθ)]
=√(sin²θ-2sinθcosθ+cos²θ)
=√(sinθ-cosθ)²
=sinθ-cosθ
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