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Topic: first four digits of n^1,000,000 (Read 487 times) |
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gkwal
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first four digits of n^1,000,000
« on: Jul 16th, 2007, 9:24pm » |
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Find a positive integer n<10,000,000 such that the first four digits (in the decimal expansion) of n^1,000,000 are all different. The problem should be solved in your head!!
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ThudnBlunder
wu::riddles Moderator Uberpuzzler
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Re: first four digits of n^1,000,000
« Reply #1 on: Jul 17th, 2007, 9:29am » |
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Considering one definition of e, 1,000,001 should do it.
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« Last Edit: Jul 18th, 2007, 3:30am by ThudnBlunder » |
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THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
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Barukh
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Re: first four digits of n^1,000,000
« Reply #2 on: Jul 17th, 2007, 10:16pm » |
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Very elegant, ThudanBlunder! Will 999999 also do?
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Sameer
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Pie = pi * e
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Re: first four digits of n^1,000,000
« Reply #3 on: Jul 17th, 2007, 10:30pm » |
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I know it's late at night but I don't get it.. (1,000,001) ^ 1,000,000 (1 + 1,000,000) ^ 1,000,000 (1 + x) ^ x Shouldn't it be (1 + 1/x) ^ x?
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"Obvious" is the most dangerous word in mathematics. --Bell, Eric Temple
Proof is an idol before which the mathematician tortures himself. Sir Arthur Eddington, quoted in Bridges to Infinity
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Barukh
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Re: first four digits of n^1,000,000
« Reply #4 on: Jul 17th, 2007, 10:45pm » |
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on Jul 17th, 2007, 10:30pm, Sameer wrote:I know it's late at night but I don't get it.. (1,000,001) ^ 1,000,000 (1 + 1,000,000) ^ 1,000,000 (1 + x) ^ x Shouldn't it be (1 + 1/x) ^ x? |
| (1 + 1,000,000) ^ 1,000,000 = [1,000,000 * (1+ 1/1,000,000)] ^ 1,000,000 ~ 1,000,000 ^ 1,000,000 * e
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Grimbal
wu::riddles Moderator Uberpuzzler
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Re: first four digits of n^1,000,000
« Reply #5 on: Jul 18th, 2007, 12:07am » |
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Out of curiosity, I tried numerically: 2^1M starts with 9900... 3^1M starts with 1797... 4^1M starts with 9802... but I could hardly do that in my head.
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ThudnBlunder
wu::riddles Moderator Uberpuzzler
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Re: first four digits of n^1,000,000
« Reply #6 on: Jul 18th, 2007, 4:36am » |
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on Jul 17th, 2007, 10:16pm, Barukh wrote: Will [hide][/hide] also do? |
| Yes, I was intending to add that we don't need n < 10 million as 1/e also works, but you have beaten me to it.
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THE MEEK SHALL INHERIT THE EARTH.....................................................................er, if that's all right with the rest of you.
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