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You are not logged in. #1 20090609 14:40:37
7*11*13!!!We most of the times think that 1001 is a prime ...well it is not Everything that has a begining has an EnD!!! #2 20090609 14:48:06
Re: 7*11*13!!!noobard, Character is who you are when no one is looking. #3 20090609 18:30:57
Re: 7*11*13!!!zzzzzzzzzz ganesh i thought being a new bee on this forum so started of with this ...........nice u told me that .... : Everything that has a begining has an EnD!!! #4 20090610 08:17:03
Re: 7*11*13!!!A result related to this discussion is the following: Suppose a and n are integers with and . If is prime then a is even and n is a power of 2. Proof Certainly a should be even, since if a is odd then is even and not 2. Suppose n = st where s is odd and s>1. Then Now so and so is not prime. Hence if is prime then n cannot have any odd divisor other than 1 so n is a power of 2. It follows from this result that is divisible by so 1001 is divisible by 11. Of course, ganesh's example shows that the converse of this result is not true since is not prime even though 10 is even and 4 is a power of 2. #6 20090610 16:38:40
Re: 7*11*13!!!Any number with an even number of digits that is a palindrome (same forwards and backwards, like 529925) is a multiple of 11. #7 20090610 18:45:34
Re: 7*11*13!!!
nice.. can be proved by divisibility rule for 11 Everything that has a begining has an EnD!!! 