化简 x2-y2+2y-1
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
x2+2y2-2xy-2y+1=0
分解因式:x2-y2-2y-1=______.
因式分解:x3+(y-1)x2-2xy-y2
2x2+xy-3y2+x+4y-1因式分解
求圆x2+y2+2x-6y+1=0与圆x2+y2+2y-..
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
因为x2+y2=2y化为x2+(y-1)2
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以(x2+y2/x
化简x2+2x+1分之x2-y2÷x+1分之x-y
请求:二元函数求极限lim (x2+y2 )1/2-sin(x2+y2 )1/2(x,y→0) (x2+y2 )3/2请