3sin^2x+-2sin^2y=2sinx sin^2x+-sin^2y=?

傅里叶级数作图f（x）=2sin[x] - sin[2x] + 2/3sin[3x] - 1/2sin[4x]我用mathematica输入程序Plot[{2sin[x],-2sin[x],2sin[x] - sin[2x],-2sin[x] + sin[2x],2sin[x] - sin[2x] + 2/3sin[3x],-2sin[x] + sin[2x] - 2/3sin[3x],2sin[x] - sin[2x] + 2/3si 3sin^2x+-2sin^2y=2sinx sin^2x+-sin^2y=? y=[sin^2(x)]*[sin^2(x)]求导 一道三角恒等式证明题请证明sin(x+y)sin(x-y)=sin^2(x)-sin^2(y) 求y=sin[sin(x^2)]的导数 sin^2x+cos^2y=1/2 求3sin^2x+sin^2y的最值 y=(sin x + COS x)^2 化简y=sin^2(x)+2sin(x)cos(x)+3cos^2(x) (cosx)^2-(cosy)^2=1/3求sin(x+y)*sin(x-y). sinx=1/3,sin(x+y)=1,求sin（2y+x）=? 已知sinx=1/3,sin(x+y)=1,则sin（2y+x)= 如果 2sin(x-y)=sin(x+y),证明 tanx= 3 tany siny=1/3,sin(x＋y)=1,求sin(2x＋y) 判断单调性 y=sin(x-π/6) y=sin(-2x+π/3) y =(cos^2) x - sin (3^x),求y' 化简sin(2x-y)*sin y+cos(2x-y)*sin y 若2sin^2x+sin^2y=3sinx,则sin^2x+sin^2y的取值范围是 sin(x+y)sin(x-y)=k,求cos^2x-cos^2y