y-xy'=b(1-x^2y'),y|x=1 =1的特解

因式分解（x+y-2xy)(x+y-2)+(xy-1)^2设x+y=a,xy=b, （x+y-2xy）（x+y-2）+（1-xy）^2记x+y=axy=b |x|/x+y/|y|+xy/|xy|= 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 已知x+y=a,x-y=b.求:x^2+y^2;xy 下列因式分解中,正确的是：.A.-2x^3-3xy^3+xy=-xy(2x^2-2y^2+1).B.-x^2-y^2=-(x+y)(x-y)C.16x^2+4y^2-16xy=4(2x-y)D.x^2)y+2xy+4y=y(x+2)^2 x-y/x+y=-1/2,x*x-xy-2y*y/x*x-3xy+2y*y的解是多少?同上,请将过程写出, 已知x+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+x(xy+y)的值 .(x+y-2)(x+y-2xy)+(xy-1)^2 (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) 已知x+y=a,x-y=b 求（1）x²+y² （2）xy 的值已知x+y=a,x-y=b 求（1）x²+y² （2）xy 对于(y一撇）y`=y/x(y-1)求导,我求的结果是y``=-y^2-y`x+y/x^2(y-1)^2 怎么不对啊,我的求导过程是：y`x(y-1) - [x(y-1)]` y y`xy-y`x-(y-1+xy`)y -y^2-y`x+yy``=-------------------------=----------------------=-----------------x^2 (y-1 [(x+y)(x-y)-(x-y)^2-4xy]/2y,其中x=1,y=-1 (x/2y)^2*y/2x-x/y^2/2y^2/x(x/x+y+2y/x+y)*xy/x+2y/(1/x+1/y)(1/a+1/b)^2/(1/a^2-1/b^2) 1/x-1/y=x,求5y+xy-5y/y-xy-x=? xy-1+x-y 已知x+y=a,x-y=b求(1)x^2+y^2;(2)xy x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2