已知5sin(α+β)+3sinα=0.求tan[α+(β/2)]cotβ/2的值.

网友回答

because:
5sin(a+b)+3sina=5sin(a+b/2)cos(b/2)+5sin(b/2)cos(a+b/2)+3sin(a+b/2)cos(b/2)-3sin(b/2)cos(a+b/2)=0
so:8sin(a+b/2)cos(b/2) =-2sin(b/2)cos(a+b/2)
so:tan(a+b/2)cos(b/2)=-1/4（左除以右）