已知π/2<b<a <3π/4,cos(a-b)=12/13,sin(a+b)=-3/5,求sin2a.

问题描述:

已知π/2<b<a <3π/4,cos(a-b)=12/13,sin(a+b)=-3/5,求sin2a.

b>π/2
-b