设xy都是正数,且xy-(x+y)=1,则x+y取值范围

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设xy都是正数,且xy-(x+y)=1,则x+y取值范围设xy都是正数,且xy-(x+y)=1,则x+y取值范围设xy都是正数,且xy-(x+y)=1,则x+y取值范围由(x+y)/2≥√xy得(x+

设xy都是正数,且xy-(x+y)=1,则x+y取值范围
设xy都是正数,且xy-(x+y)=1,则x+y取值范围

设xy都是正数,且xy-(x+y)=1,则x+y取值范围
由(x+y)/2≥√xy得(x+y)^2/4≥xy,
代入xy=1+x+y,得(x+y)^2-4(x+y)-4≥0
解得x+y≤2-2√2(舍)或x+y≥2+√2