# Formulas

A collection of random formulas.

## Formula for $$\pi$$ using the Nikalantha Series

To find a particular term in the series, assuming that the term number is x, replace ∞ with x-1, which works for everything except the first term which is of course 3.

$3+\sum_{n=1}^{\infty}\left(-1\right)^{n-1}\frac{4}{2n\cdot\left(2n+1\right)\cdot\left(2n+2\right)}$

## The quadratic formula but simpler to understand

$x = -\frac{b}{2a}\pm\sqrt{-\frac{c}{a}+\left(\frac{b}{2a}\right)^2}$

## Point Slope to Slope Intercept Form

$y=mx-mx_{1}+y_{1}$

## Tangent line of $$f(x)$$

$y=f'\left(x_1\right)\left(x-x_{1}\right)+f\left(x_{1}\right)$