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[函数] 这个取整符号的b为啥不能取1啊

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baxiannv Posted at 2022-5-29 02:53:15 From the mobile phone |Read mode

题目在右边,左边的a,b,c,d没啥用。
意思是当a≠0是,能不能有这俩点满足条件。

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 Author| baxiannv Posted at 2022-5-29 02:58:19 From the mobile phone
Last edited by hbghlyj at 2025-3-9 01:51:47$a\lceil b(x-c)\rceil+d$

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 Author| baxiannv Posted at 2022-5-29 03:11:49 From the mobile phone
Last edited by hbghlyj at 2025-3-9 02:12:00求当a≠0时,b=1时能不能找到对应的x,y(0.5,1)和(1.5,1)

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 Author| baxiannv Posted at 2022-5-29 03:25:01
Last edited by baxiannv at 2022-5-29 03:57:00c影响平移啊 可以平移0.5个单位可以把俩个点包含在1,这样b还是1呀

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hbghlyj Posted at 2025-3-9 02:10:56
Since $(0.5, 1)$ and $(1.5, 1)$ are on the graph of $f(x) = a⌈b(x-c)⌉ + d$, this means:
\[f(0.5) = a⌈b(0.5-c)⌉ + d = 1\]
\[f(1.5) = a⌈b(1.5-c)⌉ + d = 1\]
If b = 1, then:
\[a⌈0.5-c⌉ + d = 1\]
\[a⌈1.5-c⌉ + d = 1\]
Subtracting,
\[(⌈1.5-c⌉ - ⌈0.5-c⌉) a =0\]
Using $⌈0.5-c⌉=⌈1.5-c⌉ - 1$,
\[a=0\]which is not allowed.
So, it is not possible for $b = 1$.

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2025-4-20 22:16 GMT+8

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