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[函数] 函数一题

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hongxian Posted 2017-4-17 21:48 |Read mode
已知函数$f(x)=\dfrac{x+1}{x^2+1}$,则满足$\abs{f(a+1)-f(a)}=1$的实数$a$共有____________个

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色k Posted 2017-4-17 22:04
老实代进去算就行了,似乎很无趣,反正我没看出啥特别的东西

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 Author| hongxian Posted 2017-4-17 22:30
回复 2# 色k

$a=-1$应该可以,感觉还有一个无理根。

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色k Posted 2017-4-17 22:33
回复 3# hongxian

是三次方程的根,你直接分解 f(a+1)-f(a)-1 就知道了

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其妙 Posted 2017-4-19 23:56
看两个图:
3blog图片.png 4blog图片.png
楼主,本题答案是多少?
妙不可言,不明其妙,不着一字,各释其妙!

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 Author| hongxian Posted 2017-4-20 03:53
回复 5# 其妙

应该是2了,其实3楼已经说过

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