|sinx-siny|≤|x-y|如何证明

|sinx-siny|≤|x-y|如何证明 证明|x-y|≥|sinx-siny| 证明不等式|sinx-siny|《 |x-y| 请问,如何证明sinx+siny=2*sin(x+y/2)*cos(x-y/2) 证明sin(x+y)sin(x-y)=sinx-siny 证明：对x≠y,恒有|sinx-siny| 利用拉格朗日中值定理证明不等式|sinx-siny|≤|x-y| 证明 [sin(2x+y)/sinx]-2cos(x+y)=siny/sinx 证明cosx(cosx-cosy)+sinx(sinx-siny)=2sin(x-y)/2 证明sin(x+y)sin(x-y)=（sinx）^2-(siny）^2. 证明：对x不等于y,恒有｜sinx-siny｜< ｜x-y｜ 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