A Basic Proof on the square root of two

2024-10-14 • Ashiful Bhuiyan

Why \(\sqrt{2}\) is Irrational.

Working towards a contradiction, we suppose that \(\sqrt{2}\) is rational.

So $$ \sqrt{2} = \frac{p}{q} $$ for some \(p, q \in \mathbb{Z}\).

Yeah, then we get a contradiction after we see some fun stuff with \(p\) and \(q\) one being even and the other odd which makes our initial assumption false, thus proving that \(\sqrt{2}\) is not rational, and thus has to be irrational.

Decimal Expansion

\(\sqrt{2} \approx 1.4142135623730950488016887242096980785697\)

Binary Expansion of \(\sqrt{2}\)

\(\sqrt{2} \approx 1.011010100000…\)