若4x-1/(x+2)(x-1)=m/(x+2)+x/(x-1)则m等于

永艳2022-10-04 11:39:541条回答

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lxx151 共回答了23个问题 | 采纳率78.3%
4x-1/(x+2)(x-1)=m/(x+2)+x/(x-1)
(4x-1)/(x+2)(x-1)=(mx-m+x²+2x)/(x+2)(x-1)
(4x-1)/(x+2)(x-1)=[x(m-2)+x²-m]/(x+2)(x-1)
∴m-2=4
m=6
1年前

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已知x,y∈正实数,且x+y=2,求y/(x+2)+x/(y+2)的最值
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我的黑夜比白天长 共回答了15个问题 | 采纳率93.3%
y/(x+2)+x/(y+2)
=(x·(x+2)+y·(y+2))/((x+2)·(y+2))
=(x²+y²+2(x+y))/(xy+2(x+y)+4)
=((x+y)²-2xy+2(x+y))/(xy+2(x+y)+4)
=(8-2xy)/(8+xy)
=(-16-2xy+24)/(8+xy)
=-2+24/(8+xy)
∵x,y>0,x+y=2
∴0<xy≤1
∴2/3≤y/(x+2)+x/(y+2)<1
所求有最小值2/3