x-y+(y2/x+y)+(x2/x-y)
我做对了吗.x2(x-y)+y2(y-x)= x2(x-y)-y2(x-y)=x2-y2=(x+y)(x-y)
x2-x-y2-y 解法:=(x2-y2)-(x+y) =(x+y)(x-y)-(x+y) =(x+y)(x-y-1)
已知x、y满足x2+y2+174
0.5ln(x2+y2)=arctan(y/x),(x≠0,x≠y),求y’.
正整数x,y满足x2-y2=2xy,求x-y/x+y的值
整数x,y满足x2-y2=2xy,求x-y/x+y的值
已知[(x2+y2)-(x-y)2+2y(x-y)]÷4y=1,求4x/4x2-4y2-1/2x+y的值,
4y2-(x2+y)+(x2-4y2),其中x=-28 y=
已知x2+y2-10x-6y+34=0,求y\x+y的值
当x,y≥0时,曲线x2+y2=|x|+|y|互为x2
已知实数x,y 满足x2+y2+2x=0则x+y得最小值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值