已知sin(x-y)=3/5,sin(x+y)=-3/5,且x属于（兀/4,兀/2）,y属于（-3兀/4,-兀/2）,求sin2x的值.

已知sin(x+y)=1/3,sin(x-y)=1/5,则tanx/tany 已知y=3sin(x+20)+5sin(x+80),求最大值? 已知y=3sin(x+20)+5sin(x+80)求最小值如题 已知sinx=1/3,sin(x+y)=1,则sin（2y+x)= 已知sinx=3/5,x∈(π/2,π),求【sin(x+y)+sin(x-y)】/【cos（x+y）+cos（x-y）】的值 已知sin(X+Y)=2/3,sin(X-Y)=1/5,求(tanX)/(tanY)的值 已知sin(x+y)=2/3,sin(x-y)=2/5,则tanx/tany的值是多少? 已知y=3sin(x+20°)+5sin(x+80°）,求该函数最大值 已知Sin(x+y)Cosx-Cos(x-x)Sinx=3/5求tan2y的值 已知5siny=sin(2x+y),求证:tan(x+y)=3/2tanx 已知sin(x-y)cosx-cos(x-y)sinx=3/5求tan2y的值 已知x+y+z=π,证明sin(x+y)+sin(y+z)+sin(z+x)≥sin2x+sin2y+sin2z 求证sin²x-sin²y=sin(x+y)sin(x-y) 已知sin(x+π/6)=1/3,求sin(5π/6-x)+sin^2(π/3-x) 已知sin(x+π/6)=1/4,求sin(5π/6-x)+sin^2(π/3-x) 已知 Sin(X+ 派/6)=1/4求 Sin(5/6派 - X)+Sin^2 (派/3 -X) 已知Sin x+Sin y=1/2,Cos x+Cos y=根号3/3,求S求Sin(x-y)/2 已知(sinx)2-(siny)2=m求sin(x y)sin(x-y)求sin(x+y)sin(x-y)