三角函数sin(x-y)cosy+cos(x-y)siny化简要详细过程
若cos(x+y)cosy+sin(x+y)siny=0,则cosx=
已知cos(x+y)cosy+sin(x+y)siny=4/5,求tanx的值
证明sin(x+y)=sinx*cosy+cosx*siny的过程
已知sinα+sinX+sinY=0,cosα+cosX+cosY=0,则cos(X-Y) 求思路过程.跪谢
已知sinx+siny=1/3,cosx-cosy=1/5,求cos(x+y),sin(x-y).
已知sin(x-y)cosy+cos(x-y)siny≥1,则x,y的范围分别是
sin x *cos y-cos x*siny 用Mathematica怎么化简
一道高一三角函数的题sinx+siny=log7 2,cosx+cosy=log7 4,且x,y∈(0,∏),则cos(
cosx+cosy=1/2,sinx-siny=1/3,则cos(x+y)=?
已知cosx+cosy=1/2,sinx-siny=1/3,求cos(x+y)
sinx+siny=2/5,cosx+cosy=6/5,求cos(2x-2y)
sinx+siny=3/5,cosx+cosy=4/5,求cos(x-y)