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)
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)
证明sinx+siny+sinz-sin(x+y+z)=4sin((x+y)/2)sin((x+y)/2)sin((x+
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
证明sin(x+y)sin(x-y)=sinx-siny
证明sin(x+y)sin(x-y)=(sinx)^2-(siny)^2.
证明COS(X+Y)COS(X-Y)=COS^2X-SIN^2Y
sin(x+y)-sinx=2cos(x+1/2y)sin(1/2y)的详细证明步骤.
一道关于数学三角函数的题,哪位数学好的朋友帮哈忙,谢 证明sin(x+y)-sinx=2cos((2x+y)\2)sin
请问怎么证明sinX+sin(X+Y)+sin(X+2Y)/cosX+cos(X+Y)+cos(X+2Y)=tan(X+
证明 (tanX+tanY)/(tanX-tanY)=(sin(X+Y))/(sin(X-Y))
请问,如何证明sinx+siny=2*sin(x+y/2)*cos(x-y/2)
证明 [sin(2x+y)/sinx]-2cos(x+y)=siny/sinx