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[函数] 求k的最大值

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realnumber Posted at 2025-3-31 22:45:37 |Read mode
Last edited by realnumber at 2025-3-31 22:56:06对任意$x>0$,$e^x-2x\ln x\ge kx+1$恒成立,求k的最大值.


几何画板显示$f(x)=\frac{e^x}{x}-2\ln x-\frac{1}{x}$先减后增,约x=1.5附近有最小值,略比1.5大.但是数据没凑好,奇怪.小伙说题目出自同学人手一本作业本.


小猿搜题用了放缩解得k最大为$e-2\ln 2$约1.33,这个结果不对. 怀疑题目没编好.

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2025-4-20 22:18 GMT+8

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