已知cos(3π/2-α)=1/3,sin9α+β)=1.求cos(2α+β)的值已知cos(3π/2 -α)=1/3,sin（α+β)=1.求cos(2α+β)的值

已知cos(3π/2-α)=1/3,sin9α+β)=1.求cos(2α+β)的值已知cos(3π/2 -α)=1/3,sin（α+β)=1.求cos(2α+β)的值
已知cos(3π/2-α)=1/3,sin9α+β)=1.求cos(2α+β)的值
已知cos(3π/2 -α)=1/3,sin（α+β)=1.求cos(2α+β)的值

已知cos(3π/2-α)=1/3,sin9α+β)=1.求cos(2α+β)的值已知cos(3π/2 -α)=1/3,sin（α+β)=1.求cos(2α+β)的值
cos(3π/2 -α)=1/3
-sina= 1/3
sina= -1/3
sin（α+β)=1
可得cos（α+β）=0
cos(2α+β)=cosa*cos(α+β)-sinasin(α+β)= 1/3