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Math: Number Theory

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Re: Math: Number Theory [#permalink] New post 09 Feb 2014, 08:07
any body can explain that why we need to find the sum of number's factors ????
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Re: Math: Number Theory [#permalink] New post 01 May 2014, 06:50
Thanks for the post!! So helpful!
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Re: Math: Number Theory [#permalink] New post 21 Jun 2014, 03:08
Hi Bunuel,
You can change this section to.

Verifying the primality (checking whether the number is a prime) of a given number n can be done by trial division, that is to say dividing n by all integer prime numbers smaller than \sqrt{n}, thereby checking whether n is a multiple of m<\sqrt{n}.
Example: Verifying the primality of 161: \sqrt{161} is little less than 13, from integers from 2 to 13, 161 is divisible by 7, hence 161 is not prime.
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Re: Math: Number Theory [#permalink] New post 24 Jul 2014, 15:03
new to here. precious compilation. Great job
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Re: Math: Number Theory [#permalink] New post 14 Aug 2014, 16:17
Hi -

Can somebody explain where the '00' part of the 9900 in the denominator is coming from? I understand where the '99' is coming from. I copied this from the number theory section.

Thanks

" Example #2: Convert 0.2512(12) to a fraction.
1. The number consisting with non-repeating digits and repeating digits is 2512;
2. Subtract 25 (non-repeating number) from above: 2512-25=2487;
3. Divide 2487 by 9900 (two 9's as there are two digits in 12 and 2 zeros as there are two digits in 25): 2487/9900=829/3300. "
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Re: Math: Number Theory [#permalink] New post 14 Aug 2014, 19:25
Bunuel,

I am confused regarding the following exponent rule in the Math Book:
a^m^n=a^{(m^n)} and not (a^m)^n

Isn't a^m^n=a^{(m*n)}?

Thanks in advance!
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Re: Math: Number Theory [#permalink] New post 15 Aug 2014, 00:44
Expert's post
prudhviram wrote:
Bunuel,

I am confused regarding the following exponent rule in the Math Book:
a^m^n=a^{(m^n)} and not (a^m)^n

Isn't a^m^n=a^{(m*n)}?

Thanks in advance!


No.

(a^m)^n=a^{mn}

a^m^n=a^{(m^n)} and not (a^m)^n (if exponentiation is indicated by stacked symbols, the rule is to work from the top down).
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Re: Math: Number Theory [#permalink] New post 15 Aug 2014, 03:06
Bunuel wrote:
prudhviram wrote:
Bunuel,

I am confused regarding the following exponent rule in the Math Book:
a^m^n=a^{(m^n)} and not (a^m)^n

Isn't a^m^n=a^{(m*n)}?

Thanks in advance!


No.

(a^m)^n=a^{mn}

a^m^n=a^{(m^n)} and not (a^m)^n (if exponentiation is indicated by stacked symbols, the rule is to work from the top down).


I guess when the exponentiation is stacked, its not much of a confusion.

I was tripped by the following problem:
If n = 10^10 and (n^n) = (10^d), what is the value of d? (I know there is a different thread for this problem, but I wanted to refer it here for the sake of clarity)

Here the exponentiation 10^10^10^10 is not explicitly stacked. How do I approach such problems?
Re: Math: Number Theory   [#permalink] 15 Aug 2014, 03:06
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