Talk:Mathematical Proof/Methods of Proof/Proof by Contradiction

More Classical examples?
The proof that there are infinite many prime numbers p1,p2,...,pn can be done really elegant by assuming that there are only a finite nunmer of primes, and thet construct a new number (p1*p2*...*pn +1)

that is not divisible by any of the original primes, and therefore, must be either a new prime, or a product of new primes.

Who is the audience for this? If somebody doesn't know what a proof by contradiction is, then they are certainly not going to understand what a topological space is.