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[函数] 求范围

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caesarxiu posted 2016-12-28 23:56 |Read mode
已知函数$f(x)=\sqrt{1-x}+\sqrt{1+x}$,若$x,y$满足$f(x+1)-f(y)>0$,则$x^2+y^2-2x+1$的取值范围是____

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kuing posted 2016-12-29 01:44
这个没啥难度吧,由 f 的定义域、奇偶性、单调性知 f(x+1)>f(y) <=> |x+1|<|y|<=1,画个图就完了

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original poster caesarxiu posted 2016-12-29 13:03
恩,对。我也没怎么看,看了一下二元还带根号手快,就发了,版主可以删掉此贴。

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isee posted 2016-12-29 14:08
恩,对。我也没怎么看,看了一下二元还带根号手快,就发了,版主可以删掉此贴。 ...
caesarxiu 发表于 2016-12-29 13:03

    题都是好题,留着,写个代码也不容易。

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踏歌而来 posted 2016-12-30 12:32
不知为什么,经常显示不正常:
奇怪.PNG ]g]

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kuing posted 2016-12-30 14:00
回复 5# 踏歌而来

浏览器问题吧,上面我都没有使用代码,肯定不是mathjax公式的问题

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踏歌而来 posted 2016-12-30 16:38
是的,我用的是360浏览器,刚才用微软的ie打开,显示正常。
另外,这个范围是(0,2]吧。

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kuing posted 2016-12-30 16:57
回复 7# 踏歌而来

想了下图象应该是 (2,10)

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踏歌而来 posted 2016-12-31 18:08
是的,我搞错了,谢谢指正!

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