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#1 2008-11-04 09:10:20

GemmaJ1988
Member
Registered: 2008-10-08
Posts: 39

primes

i have the following question
write

as a product of distinct primes.
does anyone know what this is actually asking me to do.
please help

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#2 2008-11-04 18:25:36

Ricky
Moderator
Registered: 2005-12-04
Posts: 3,791

Re: primes

The "question" is asking you to prove that given any natural number n, we may write n as a product of distinct primes.

90 = 2*45 = 2*(3*15) = 2*(3*(3*5))

Above is the basic method used to prove it, though a nicer (but slightly less obvious) way exists.


"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

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#3 2008-11-05 02:16:19

GemmaJ1988
Member
Registered: 2008-10-08
Posts: 39

Re: primes

is n not already expressed as its product of distinct primes then?

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#4 2008-11-05 04:29:17

Ricky
Moderator
Registered: 2005-12-04
Posts: 3,791

Re: primes

You need to prove that n _can be_ expressed as a product of primes.


"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

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#5 2008-11-05 11:15:28

GemmaJ1988
Member
Registered: 2008-10-08
Posts: 39

Re: primes

so i've looked up the fundamental theorem of arithmetic and ive tried to apply this to n
i got



if we set



does this seem remotely along the right lines?

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#6 2008-11-05 11:27:36

Ricky
Moderator
Registered: 2005-12-04
Posts: 3,791

Re: primes

No.  The Fundamental Theorem of Arithmetic is specifically what you are trying to prove.


"In the real world, this would be a problem.  But in mathematics, we can just define a place where this problem doesn't exist.  So we'll go ahead and do that now..."

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