若1/x+1/y=2,则 x/(3x+3y)+(y+2xy)/(3x+3y)=

问题描述:

若1/x+1/y=2,则 x/(3x+3y)+(y+2xy)/(3x+3y)=
1个回答 分类:数学 2014-11-10

问题解答:

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x/(3x+3y)+(y+2xy)/(3x+3y)=
(x+y+2xy)/3(x+y)=1/3+2/3(xy/x+y)=
1/3+2/3[1/(1/x+1/y)]=1/3+1/3=2/3
 
 
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