关于三角的化简
1.5π<α<2π,要求化简 [根号(1-cosα)+根号(1+cosα)]÷[根号(1-cosα)-根号(1+cosα)]+根号(1+sinα)÷根号(1-sinα)
人气:471 ℃ 时间:2020-07-17 12:45:56
解答
[√(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
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