diff --git a/_posts/2024/2024-05-23-a-note-on-the-final-digit-of-pi.md b/_posts/2024/2024-05-23-a-note-on-the-final-digit-of-pi.md new file mode 100644 index 0000000..bcab0af --- /dev/null +++ b/_posts/2024/2024-05-23-a-note-on-the-final-digit-of-pi.md @@ -0,0 +1,53 @@ +--- +id: a-note-on-the-final-digit-of-pi +title: A Note on the Final Digit of $\pi$ +date: 2024-05-23 +author: k3jph +layout: post +permalink: /2024/05/23/a-note-on-the-final-digit-of-pi +featured_image: /assets/img/2024/a-note-on-the-final-digit-of-pi.webp +categories: +- Blog +tags: +- mathematics +- number theory +- proofs +--- + +I recently saw someone wearing a t-shirt that said, "My password is the +last 8 digits of $\pi$." The joke, of course, lies in the fact that +$\pi$ (pi) is an irrational number, meaning its decimal expansion goes +on forever without repeating. Consequently, there are no "last" digits +to know. However, a fascinating twist exists when considering $\pi$ in +binary form. + +> **Theorem.** _The final digit of $\pi$ in binary is 1._ +> +> _Proof._ To understand why this is true, let's consider the nature of +> binary representations. In binary (base-2), every number is +> represented as a sequence of 0s and 1s. +> +> Now, consider $\pi$ in its binary form. If we suppose the last digit is +> 0, we encounter a logical inconsistency. If there were a final 0, it +> could be removed, as trailing zeros in binary (or any number base) do +> not affect the value of the number. This removal would imply that the +> number is not infinite, contradicting the fact that $\pi$ is +> irrational and has an endless, non-repeating sequence of digits. +> +> Therefore, the only consistent option is that the final digit in the +> binary representation of $\pi$ must be 1. This ensures that $\pi$ retains +> its infinite nature. + +This elegant and humorous observation underlines the intriguing +properties of irrational numbers and their representations in different +numeral systems. + +The joke about the t-shirt cleverly plays on our understanding of +infinity and irrational numbers. While it's true that we cannot specify +the "last" digits of $\pi$ in decimal form, the binary perspective offers a +unique insight. + +For those who love diving deeper into mathematics, exploring the +properties of $\pi$ across different bases can be a delightful exercise. It +enriches our appreciation of mathematical beauty and provides a fun way +to engage with infinity and number theory concepts. diff --git a/assets/img/2024/a-note-on-the-final-digit-of-pi.webp b/assets/img/2024/a-note-on-the-final-digit-of-pi.webp new file mode 100644 index 0000000..50b7e87 Binary files /dev/null and b/assets/img/2024/a-note-on-the-final-digit-of-pi.webp differ