已知2x=y,求代数式【（x^2+y^2）-(x^2-y^2)+2y(x-y)】/(4y)的值.

已知2x=y,求代数式【（x^2+y^2）-(x^2-y^2)+2y(x-y)】/(4y)的值.
已知2x=y,求代数式【（x^2+y^2）-(x^2-y^2)+2y(x-y)】/(4y)的值.

已知2x=y,求代数式【（x^2+y^2）-(x^2-y^2)+2y(x-y)】/(4y)的值.
【（x^2+y^2）-(x^2-y^2)+2y(x-y)】/(4y)
=[（x^2+y^2）-(x^2-y^2)+2xy-2y^2)]/4y
=[x^2+y^2+2xy-(x^2+y^2)]/4y
=2xy/4y
=x/2y
=x/4x
=1/4

原式=【（y+y^2）-(y-y^2)+2y(x-y)】/(4y)
=【3y-3y+2xy-2y2】/（4y）
=(2xy-2y2）/(4y)
=0.5x-0.5y
=-0.5x

原式=[(x^2+4x^2)-(x^2-4x^2)+4x(x-2x)]/8x
=(5x^2+3x^2+4x^2-8x^2)/8x
=4x^2/8x
=1/2x
小生天资愚钝，解不出来.........