证明 [sin(2x+y)/sinx]-2cos(x+y)=siny/sinx

证明sin(x+y)sin(x-y)=sinx-siny 证明 [sin(2x+y)/sinx]-2cos(x+y)=siny/sinx 证明sin(x+y)sin(x-y)=（sinx）^2-(siny）^2. 证明cosx(cosx-cosy)+sinx(sinx-siny)=2sin(x-y)/2 y=[√（1+sin^2x)+sinx+1]/[√（1+sin^2x)+sinx-1]判断并证明奇偶性 证明sinx+siny+sinz-sin(x+y+z)=4sin((x+y)/2)sin((x+y)/2)sin((x+y)/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) 请问,如何证明sinx+siny=2*sin(x+y/2)*cos(x-y/2) 证明y=sinx+sinπx不是周期函数 请问怎么证明sinX+sin(X+Y)+sin(X+2Y)/cosX+cos(X+Y)+cos(X+2Y)=tan(X+Y), 判断函数y=lg[sinx++√(1+sin^2x)]的奇偶性并证明 证明sinx+cos(x+y)siny/cosx-sin(x+y)siny=tan(x+y) y=sinx/sin^2x-sinx+2求最值 证明:sin2x=2sinx*cosx为什么sin(x+x)=sinx*cosx+cosx*sinx? sinx连续性的证明.Δy=sin(x+Δx)-sin(x)=2sin(Δx/2)*cos(x+Δx/2)sinx连续性的证明.Δy=sin(x+Δx)-sin(x)=2sin(Δx/2)*cos(x+Δx/2)然后知道cos(x+Δx/2) sin(x+y)-sinx=2cos(x+1/2y）sin(1/2y)的详细证明步骤.越详细越好. y=sinx+sin|x| 证明x∈(0,π/2),cos(cosx)>sin(sinx)