x^2+4y^2-4x+4y+5=0,求[（x^4-y^4)/xy]*[(2x^2-xy)/(xy-y^2)]/{(x^2+y^2)/y}^2.
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x^2+4y^2-4x+4y+5=0,求[（x^4-y^4)/xy]*[(2x^2-xy)/(xy-y^2)]/{(x^2+y^2)/y}^2.
x^2+4y^2-4x+4y+5=0,求[（x^4-y^4)/xy]*[(2x^2-xy)/(xy-y^2)]/{(x^2+y^2)/y}^2.
x^2+4y^2-4x+4y+5=0,求[（x^4-y^4)/xy]*[(2x^2-xy)/(xy-y^2)]/{(x^2+y^2)/y}^2.
x^2+4y^2-4x+4y+5=0,
x^2-4x+4+4y^2+4y+1=0,
(x-2)^2+(2y+1)^2=0
x=2,y=-1/2
[（x^4-y^4)/xy]*[(2x^2-xy)/(xy-y^2)]/{(x^2+y^2)/y}^2.
=[(x^2-y^2)(x^2+y^2)/xy]*[x(2x-y)/y(x-y)]/{(x^2+y^2)/y}^2.
=[(x^2-y^2)(x^2+y^2)/xy]*[x(2x-y)/y(x-y)]*{y/(x^2+y^2)}^2.
=[(x^2-y^2)(x^2+y^2)/xy]*[x(2x-y)/y(x-y)]*y^2/(x^2+y^2)^2.
=[(x^2-y^2)/xy]*[x(2x-y)/y(x-y)]*y^2/(x^2+y^2).
=(x^2-y^2)*(2x-y)/(x-y)*1/(x^2+y^2).
=(x-y)(x+y)*(2x-y)/(x-y)*1/(x^2+y^2).
=(x+y)*(2x-y)/(x^2+y^2).
=[2+(-1/2)]/[2^2+(-1/2)^2]
=(3/2)/(17/4)
=3/2*4/17
=6/17
∵x^2+4y^2-4x+4y+5=0
∴（x^2-4x+4）+（4y^2+4y+1）=0
∴（x-2）²+（2y+1）²=0
∴x-2=0，2y+1=0
∴x=2，y=-1／2
[（x^4-y^4)/xy]*[(2x^2-xy)/(xy-y^2)]/{(x^2+y^2)/y}^2.
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∵x^2+4y^2-4x+4y+5=0
∴（x^2-4x+4）+（4y^2+4y+1）=0
∴（x-2）²+（2y+1）²=0
∴x-2=0，2y+1=0
∴x=2，y=-1／2
[（x^4-y^4)/xy]*[(2x^2-xy)/(xy-y^2)]/{(x^2+y^2)/y}^2.
=｛[2^4-（-1／2）^4]÷2×（-1／2）｝×｛[2×2²-2×（-1／2）]÷[-2×（-1／2）-（-1／2）²]÷｛[2²+（-1／2）²]÷（-1／2）｝²
=（-4+1／64）×9÷（3／4）÷（289／4）
=765／1156
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