锐角α,β满足sinα=√5/5,cosβ=3√10/10
则:cosα=2√5/5,sinβ=√10/10
sinα>sinβ
则:α>β
cos(α-β)=cosαcosβ+sinαsinβ
=(2√5/5)(3√10/10)+(√5/5)(√10/10)
=30√2/50+5√2/50
=35√2/50
=7√2/10
所以,α-β=arccos(7√2/10)
已知锐角α,β满足sinα=根号5/5,cosβ=3根号10/10,则α-β等于多少
已知锐角α,β满足sinα=根号5/5,cosβ=3根号10/10,则α-β等于多少
其他人气:375 ℃时间:2019-10-24 03:19:47
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