若cosα=1/5α属于(0.π/2)则sin(α-π/3)求答案
问题描述：
若cosα=1/5α属于(0.π/2)则sin(α-π/3)
求答案
答
cosα=1/5
那么sinα=（2*根号6）/5
sin（α-π/3）=sinα*cosπ/3-cosα*sinπ/3
=[（2*根号6）/5]*1/2+(1/5)*（根号3）/2
=（根号6）/5+(根号3)/10
希望能帮助你~
答
由cosα=1/5和α属于(0.π/2)得：sinα=2√ 6/5,
所以：sin(α-π/3)=(sinα)/2-(√3cosα)/2=√ 6/5-3√2/5
答
cosα=1/5α属于(0.π/2)
sinα=√1-cos平方α=2√6/5
所以
sin(α-π/3)
=sinαcosπ/3-cosαsinπ/3
=2√6/5·1/2-1/5·√3/2
=(2√6-√3)/10