二次型f(x,y) = x2-2xy+y2的系数矩阵是
已知:x=3,y=-5,x2-2xy+y2/x2-y2的值是
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
25(x2+ 2xy +y2)-9(x2-2xy+y2)因式分解.x2,y2是x平方,y平方的意思.2xy就是2xy.快
已知(x+y)2=25,xy=3,求x2+y2求x2+y2的值答案是?
若X2+Y2-2X-6Y+10=0 ,求(x2-y2)/xy的值
求函数f(x,y)=x2+xy+y2-6x-3y的极致
设x,y是实数,且 x2+xy+y2=3.那么,x2-xy+y2的取值范围是?
正数xy满足x2-y2=2xy,求x+y分之x-y的值
已知x、y是实数且满足x2+xy+y2-2=0,设M=x2-xy+y2,则M的取值范围是______.
已知X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
已知实数x,y满足x2+xy+y2=3,则x2-xy+y2的最小值
已知x(x-1)+(y-x2)=6,则代数式x2+y2/2-xy的值是