sin(x-y)cosx-cos(y-x)sinx=3/5 y是第三象限角 求sin(y+5π/4)
cos(x+y)sinx-sin(x+y)cosx
已知sinx+siny=1/3,cosx-cosy=1/5,求cos(x+y),sin(x-y).
sinx*sin(x+y)+cosx*cos(x+y)等于?
化简sin(x+y)sinx+cos(x+y)cosx等于?
化简sin(x+y)sinx+cos(x+y)cosx
化简cos(x+y)sinx-sin(x+y)cosx
y=cosX,y= - cos(-X) 与y=sinX,y= - sin(-X) 为什么?
已知cos(x-y)cosx+sin(x-y)sinx=3/5,则cosy的值为
y=sin²X+2sinX*cosX+3COS²X的最大值是?
为什么y=sinx,y=-sin(-x)=sinx,y=cosx,y=-cos(-x)=-cosx
求函数y=2sinx*cos(3π/2+x)+√3cosx*sin(π+x)+sin(π/2+x)*cosx的最小正周期
已知函数y=sin平方x+2sinx·cosx+3cos平方 求y的取值范围