# Math Help - Prove that if n>=2 and not prime, then n has a prime divisor p<=(sq.root)n

1. ## Prove that if n>=2 and not prime, then n has a prime divisor p<=(sq.root)n

Hello All,

Does a solution to such as problem as this exist? In proving this, would it be advisable to attempt "reductio ad absurdum" for something like this and then extend it?

Thank you for your time.

2. ## Re: Prove that if n>=2 and not prime, then n has a prime divisor p<=(sq.root)n

Originally Posted by panglot
Hello All,

Does a solution to such as problem as this exist? In proving this, would it be advisable to attempt "reductio ad absurdum" for something like this and then extend it?

Thank you for your time.
Hint:

Read here: Sieve of Eratosthenes - Wikipedia, the free encyclopedia