x2-y2=x-y 求y'
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
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
x2+y2=1,求x+y的最小值
2010.09.已知x、y为实数,且(x2+y2)(x2+y2+1)=20,求x2+y2的值
已知x,y为实数,且(x2 +y2)(x2 +y2+2)=3.求x2 +y2的值
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
已知圆x2+y2-2x-2y+1=0求x2+y2的最大值
1.已知X2+Y2-4X-6Y+13=0,求Y2-X2的值
已知x2-4x+y2-6y+13=0求x2+y2的值?
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/xy的值