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幼苗
共回答了18个问题采纳率:83.3% 举报
[√(1-cosα)+√(1+cosα)]÷[√(1-cosα)-√(1+cosα)]+√(1+sinα)÷√(1-sinα)
=[sinα/2-cosα/2]/[sinα/2+cosα/2) + (sinα/2+cosα/2)/(sinα/2-cosα/2)
=2[(sinα/2)^2+(cosα/2)^2]/[(sinα/2)^2-(cosα/2)^2]
=2/(-cosα)
√(1-cosα)=√2(sinα/2)
√(1+cosα)=-√2(cosα/2) cosα/2
1年前
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