已知α、β都为锐角,且满足sinα=1/7,cos(α+β)=5√3/14

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已知α、β都为锐角,且满足sinα=1/7,cos(α+β)=5√3/14
已知α、β都为锐角,且满足sinα=1/7,cos(α+β)=5√3/14

已知α、β都为锐角,且满足sinα=1/7,cos(α+β)=5√3/14
sinα=1/7,cos(α+β)=5√3/14
cosα=4√3/7,sin(α+β)=11/14
cosβ
=cos(α+β-α)
=cos( α+β)cosα+sin(α+β)sinα
=71/98
sinβ=39√3/98