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.

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/19 19:29:43
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.
xRJ@~$?l3ݦHH@@Eإ (=^ ^SߤТObŊs&6f"8v#Uד0M

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.

全部展开

∵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

收起