Tag: number theory


Approximating Pi (Happy Pi Day)

Posted in Mathematics

permalink

Favorite Pi Approximations

What's your favorite \(\pi\) approximation?

Some of my favorite approximations of \(\pi\) come from Ramanujan-Sato series. These are mathematical series that generalize from a remarkable formula for \(\pi\) given by Srinivasa Ramanujan, an Indian mathematician:

$$ \pi^{-1} = \dfrac{\sqrt{8}}{99^2} \sum_{k \geq 0} \dfrac{ (4k)! }{ \left( 4^k k! \right)^4 } \dfrac{ 1103 + 26390k }{ 99^{4k} } $$

This completely novel formula opened up new branches of mathematics and provided a whole new class of \(\pi\) approximations (the Ramanujan-Sato series) and approximations that are extremely accurate, making them very useful for computer applications. (Each term of …



Tags:    pi    continued fractions    number theory    mathematics    python    irrational numbers   


Euler's Theorem, the Totient Function, and Calculating Totients By Hand

Posted in Mathematics

permalink

Table of Contents

Introduction

Today we're going to delve into a little bit of number theory.

In number theory, we are usually dealing with modular arithmetic - expressions of the form:

$$ a \equiv b \mod m $$

or

$$ f(x) \equiv 0 \mod m $$

The mod indicates we're doing modular arithmetic, which is (formally) an algebraic system called a ring, which consists of the integers 0 through m.

An analogy to modular arithmetic is the way that the sine and cosine function "wrap around," and

$$ \sin \left …


Tags:    mathematics    factors    number theory    euler   


Computing Square Roots: Part 2: Using Continued Fractions

Posted in Mathematics

permalink

Table of Contents

Continued Fractions

Let's start part 2 of our discussion of computing square roots by talking about continued fractions. When we first learn mathematics, we learn to count in the base 10 system: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. We can construct representations of all of the integers using these 10 digits, by arranging them in a different order. So, for example, saying 125 is equivalent to saying …




Computing Square Roots: Part 1: Using Newton's Method

Posted in Mathematics

permalink

Table of Contents

Newton's Method for Finding Roots of Equations

Suppose we have a function \(f(x)\) and we want to compute values of \(x\) for which \(f(x)=0\). These values of \(x\) are called the roots of \(f(x)\).

We can compute the roots using Newton's Method, which utilizes the derivative of the function to iteratively compute the roots of the function.

Newton's method begins with an initial guess. It evaluates the derivative …