sinα=1/3,cos(α+β)=1
cosα=±√(1-sin²α)=±2√2/3
sin(α+β)=±√[1-cos²(α+β)]=0
sin(2α+β)
=sin[α+(α+β)]
=sinαcos(α+β)+cosαsin(α+β)
=1/3*1+0
=1/3
sinα=1/3,cos(α+β)=1
cosα=±√(1-sin²α)=±2√2/3
sin(α+β)=±√[1-cos²(α+β)]=0
sin(2α+β)
=sin[α+(α+β)]
=sinαcos(α+β)+cosαsin(α+β)
=1/3*1+0
=1/3