sinx siny-sin(x y)如何化简

sinx siny-sin(x y)如何化简 证明sin(x+y)sin(x-y)=sinx-siny 请问,如何证明sinx+siny=2*sin(x+y/2)*cos(x-y/2) |sinx-siny|≤|x-y|如何证明 证明sinx+cos(x+y)siny/cosx-sin(x+y)siny=tan(x+y) 为什么sinx*cosy-cosx*siny=sin(x-y) 求函数z=sinx+siny+sin(x+y)(0 存在sin( x -y) = sinX-sinY吗 讨论大学函数连续性sin(x+y)-sinx=2siny/2 * cos(x+y/2)sin(x+y)-sinx=2siny/2 * cos(x+y/2)如何推导?y=delta(x) 证明 [sin(2x+y)/sinx]-2cos(x+y)=siny/sinx 求证sin（2x+y)/sinx-2cos(x+y)=siny/sinx 求证：sin(2x+y)/sinx-2cos(x+y)=siny/sinx 证明sin(x+y)sin(x-y)=（sinx）^2-(siny）^2. 三角不等式证明证明sin(x+y)+sin(y+z)+sin(z+x)>sinx+siny+sinz+sin(x+y+z) 求下列导数：sin(x+y)=sinx+siny e^x+x=e^y+y 证明cosx(cosx-cosy)+sinx(sinx-siny)=2sin(x-y)/2 为什么sin（x+y) - sinx = 2cos(x+y/2)siny/2 求推导sinx-siny=2cos（(x+y)/2)sin((x-y)/2)