证明题:x,y为锐角,3*(sinx)^2+2*(siny)^2=1,3*sin2x-2*sin2y=0,求证:x+2y
已知sinx-siny=1/2,cosx-cosy=1/2,x、y均为锐角,求sin(x-y)
求证:sin(2x+y)/sinx-2cos(x+y)=siny/sinx
证明 [sin(2x+y)/sinx]-2cos(x+y)=siny/sinx
已知sinx-siny=-2/3,cosx-cosy=2/3,且x.y为锐角,则tan(x-y)的值为?
求证sinx+siny=2sin(x+y)/2*cos(x-y)/2
求证|sinx-siny|=|2sin[(x-y)/2]cos[(x+y)/2]|
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)^2-(siny)^2.
证明cosx(cosx-cosy)+sinx(sinx-siny)=2sin(x-y)/2
证明sinx+siny+sinz-sin(x+y+z)=4sin((x+y)/2)sin((x+y)/2)sin((x+
求证:sin(x-y)/(sinx-siny)=cos[(x-y)/2]/cos[(x+y)/2]
已知x,y为锐角,tanx=1/7,siny=√10/10,求x+2y.