y=cos(x/2-π/4)=sin[(x/2-π/4)+ π/2]

y=sin（-3x) =-sin3x y=cos(3x+π\4) =cos(π/2+3x-π/4) =-sin(3x-π 1.y=cos^4x+sin^4x 求周期 2.y=（sin2x+sin（2x+π/3)）/（ cos2x+cos（2x y=sin(2x-π/4)+cos(3x+π/3)的导数 已知f(x)=cos^2x+sinxcosx g(x)=2sin(x+π/4)sin(x-π/4) MATLAB画图,y=sin(x)*(cos(x)-1)/((2*sin(x.^2)+4*cos(x)).^0.5)-( 若x属于（0,π/4）,求函数y=cos^2x-sin^x+2sinxcosx的值域 设f(x)=4cos(ωx-π/6)sinωx-cos(2ωx+π),其中ω>0,(1)求函数y=f y=sin^2x-3sinxcosx+4cos^2x是否等于y=sin^2x+cos^2x+3cos^2x-3/2*si sin(x+y)sin(x-y)=k,求cos^2x-cos^2y 函数y=cos(2x-π/4)怎样化成sin形式 证明COS（X+Y）COS（X-Y）=COS^2X-SIN^2Y 求证:sin(π/4+x)/sin(π/4-x)+cos(π/4+x)/(π/4-x)=2/cos2x