化简:1+cosθ－sinθ/1－cosθ－sinθ+1－cosθ－sinθ/1+cosθ－sin
化简:1+cosθ－sinθ/1－cosθ－sinθ+1－cosθ－sinθ/1+cosθ－sinθ....
化简:1+cosθ－sinθ/1－cosθ－sinθ+1－cosθ－sinθ/1+cosθ－sinθ.
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[(1+cosθ－sinθ)/(1－cosθ－sinθ)]+[(1－cosθ－sinθ)]/(1+cosθ－sinθ)].
=[2(cosθ/2)^2-2sinθ/2cosθ/2]/[2(sinθ/2)^2-2sinθ/2cosθ/2]
+[2(sinθ/2)^2-2sinθ/2cosθ/2]/[2(cosθ/2)^2-2sinθ/2cosθ/2]
=[cosθ/2(cosθ/2-sinθ/2)]/[sinθ/2(sinθ/2-cosθ/2]
+[sinθ/2(sinθ/2-cosθ/2]/cosθ/2(cosθ/2-sinθ/2)]
=[-cosθ/2/sinθ/2]-[sinθ/2/cosθ/2]
=-[(sinθ/2)^2+(cosθ/2)^2]/(sinθ/2cosθ/2)
=-1/sinθ/2cosθ/2
=-2/sinθ
=[2(cosθ/2)^2-2sinθ/2cosθ/2]/[2(sinθ/2)^2-2sinθ/2cosθ/2]
+[2(sinθ/2)^2-2sinθ/2cosθ/2]/[2(cosθ/2)^2-2sinθ/2cosθ/2]
=[cosθ/2(cosθ/2-sinθ/2)]/[sinθ/2(sinθ/2-cosθ/2]
+[sinθ/2(sinθ/2-cosθ/2]/cosθ/2(cosθ/2-sinθ/2)]
=[-cosθ/2/sinθ/2]-[sinθ/2/cosθ/2]
=-[(sinθ/2)^2+(cosθ/2)^2]/(sinθ/2cosθ/2)
=-1/sinθ/2cosθ/2
=-2/sinθ
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