(COSx)^2--(COSy)^2=(根号3)/2,求SIN(X+Y).SIN(X-Y)=
求证cosx-cosy=-2sin (x+y/2)*sin (x-y/2)
sinx+siny=1/2,cosx+cosy=(根号3)/3,求sin[(x-y)/2]
sinx+siny=-1/3 cosx+cosy=1/2,求sin(x+y)的值.
证明cosx(cosx-cosy)+sinx(sinx-siny)=2sin(x-y)/2
已知sinx-siny=1/2,cosx-cosy=1/2,x、y均为锐角,求sin(x-y)
Y=2COSX·sin(X+pai/3)-根号3sin平方X+sinX·cosX
sinx+siny=√2/2 cosx+cosy=√6/2 求sin(x+y)求解答.
已知tanx=-1/3,cosy=根号5/5,求tan(x+y)的值和函数f(x)=根号2sin(a-x)+cos(a+
求函数y=(sin²x+3cosx-4)/(cosx-2)的值域
求解一阶微分方程:(3x+2cosy)dx-x sin y d y=0
已知sinx+siny=1/3,cosx-cosy=1/5,求cos(x+y),sin(x-y).
求函数值域 y=sinx+cosx如何推出y=根号2×sin(x+π/4)