(sinθ+cosθ-1)(sinθ-cosθ+1)/sin2θ=tan2/θ

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(sinθ+cosθ-1)(sinθ-cosθ+1)/sin2θ=tan2/θ(sinθ+cosθ-1)(sinθ-cosθ+1)/sin2θ=tan2/θ(sinθ+cosθ-1)(sinθ-cos

(sinθ+cosθ-1)(sinθ-cosθ+1)/sin2θ=tan2/θ
(sinθ+cosθ-1)(sinθ-cosθ+1)/sin2θ=tan2/θ

(sinθ+cosθ-1)(sinθ-cosθ+1)/sin2θ=tan2/θ
原式=(sinθ²-(cosθ-1)²)/sin2θ
=(2cosθ-2cosθ2)/sin2θ
=(1-cosθ)/sinθ
= ( 2cos(θ/2) )2/sinθ
=tan(θ/2)

原式=[sin&2a-(cosa-1)&2]/sin2a
=(-2cos&2a+2cosa)/2sinacosa
=(-cosa+1)/sina
=2sin&2(a/2)/2sin(a/2)cos(a/2)
=tana/2