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Martin

Fri Jul 18, 2003 2:50 am


Proof

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Alright, these are just some mathematical proof questions. The first ones'll be pretty simple, but they'll get progressively more difficult. I'm going to keep this thread clean, so any off topic remarks (pretty much anything that's not a solution) will be deleted. 

Alright, first question, for 10 bits (each question will be worth 10 bits more than the previous).

Prove that a number ending in 5 ends in 25 when squared.
ex. 35*35 = 1225. Note the 25


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Crono

Fri Jul 18, 2003 11:01 am



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very simple question, first, let us call the number 10x + 5, x can b greater than 9 if u want,

squaring it gets 100x^2 + 100x + 25, obviously it has to end in 25, duh...


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SilverSprite

Fri Jul 18, 2003 1:07 pm



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Thats no faiiiiiir Crono's too smart to do these questions!!!!! My turn to answer it. Let the number be 10a + 5. Squaring this number gives 100a^2 + 100a + 25. The required result.


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Crono

Fri Jul 18, 2003 2:11 pm



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doesnt matter, a question is a question, doesnt matter whoz doin it, bitz plz


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bugzpodder

Fri Jul 18, 2003 4:19 pm



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Darkness still owes me 500 bits...  Crono needs harder questions, such as this one: Show that for each prime p, there exists a prime q such that n^p-p is not divisible by q for any positive integer n.


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Crono

Sat Jul 19, 2003 12:54 pm



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500??? wow, tat's quite a few
i'll work at ur question, it mite take a while, i'll c wut i can do
hope other ppl dun get tis b4 me, tat'd make me look bad, heheh  :oops: