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化简:(sinα)^2+(sinβ)^2-(sinα)^2(sinβ)^2+cos2αcos2β

分类: 作业答案 • 2022-01-09 18:02:45
问题描述：

化简:(sinα)^2+(sinβ)^2-(sinα)^2(sinβ)^2+cos2αcos2β

答

sinα=(1-cos2α)/2
(sinα)^2+(sinβ)^2-(sinα)^2(sinβ)^2+cos2αcos2β
=(1-cos2α)/2+(1-cos2β)/2-(1-cos2α)/2*(1-cos2α)/2+cos2αcos2β
=(1+cos2αcos2β)*0.75

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