已知x>y>0,且xy=3,则(x^2+y^2)/(x-y)的最小值是
已知x>y>0,且xy=3,则(x^2+y^2)/(x-y)的最小值是
数学人气:623 ℃时间:2019-08-17 20:07:41
优质解答
(x^2+y^2)/(x-y)=[(x-y)^2+2xy]/(x-y)=(x-y)+6/(x-y)>=2√[(x-y)*6/(x-y)]=2√6[(x-y)^2+2xy]/(x-y)=(x-y)+6/(x-y) 为什么(x-y)^2 变成了 (x-y)? 那个^2跑哪去了?[(x-y)^2+2xy]/(x-y)=(x-y)^2/(x-y)+2xy/(x-y)=(x-y)+6/(x-y)
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