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**Prime Numbers**

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** Statement ** All Prime numbers are odd

** Proof **

Lemma: A prime number greater than 2 is odd.

Proof: Assume the contrary, then 2 divides the number therefore it is not prime.

Now,

1. All prime numbers greater than 2 are odd

2. 2 is the only even prime number. Therefore, it is the oddest.

From 1 and 2, all prime numbers are odd

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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**Statement** There are infinitely many prime numbers

**Proof**

Suppose that p1,p2,...,pn are n distinct primes. We construct a

prime pn+1 not equal to any of p1, . . . , pn, as follows. If

N =p1p2p3···pn +1

then there is a factorization N = q1q2 ···qm

with each qi prime and m≥1. If q1 =pi for some i,then pi |N. We also have pi |N−1, so pi |1=N−(N−1),which is a contradiction. Thus the prime pn+1 = q1 is not in the list p1, . . . , pn, and we have constructed our new prime.

**Statement** There are infinitely many composites.

**Proof:** To obtain a new composite number, multiply together the first n composite numbers and dont add 1.

*Last edited by Agnishom (2013-04-21 01:47:53)*

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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Agnishom wrote:

StatementThere are infinitely many composites.

Proof:To obtain a new composite number, multiply together the first n composite numbers and dont add 1.

This proof is valid and correct.

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Thanks

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,646

It's not really a joke.

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Why not?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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Is not funny because it is valid?

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

'But our love is like the wind. I can't see it but I can feel it.' -A Walk to remember

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**yazz****Member**- Registered: 2014-01-14
- Posts: 425

it would be really funny when we talk about these in classes when the chapters are going very seriously.

Knowledge is knowing that a tomato is a

fruit, but Wisdom is knowing not to put it in a fruit salad .

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**Prime Numbers**