Tuesday, April 13, 2010

Square root of 2 is irrational.

Proof by infinite descent:
=================

Proving sq.root(2) is irrational is a perfect instance.

Let us say, sq.root(2) a rational number.

x = sq.root(2) . y

x ^ 2 = 2 . y ^ 2 => proves x is even. let us further assume, x = 2 . z

4 z ^ 2 = 2 . y ^ 2 => y^2 = 2 . z^2 => proves y is even.

So, x and y are both even, which can be reduced further and further as proved above. So, x / y, representation of sq.root(2) doesn't exist, and hence irrational.


No comments:

Post a Comment