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