Solve equations

This is a simple libary for solving equations of linear($x$), quadratic($x^2$), cubic($x^3$), and quartic($x^4$) equations.

Install

npm install -S @littlefattie/solve-equations

Usage

import { solveLinear, solveQuadratic, solveCubic, solveQuartic } from "@littlefattie/solve-equations";

// This should be x = -0.5
const res1 = solveLinear(2, 1);

// This should be
//   x1,2 = -1/2 +/- sqrt(3)/2 i
// for equation $x^2+x+1=0$
const res2 = solveQuadratic(1, 1, 1);

// This should be
//   x1 = 1
//   x2,3 = -1/2 +/- sqrt(3)/2 i
// for equation (x-1)(x^2+x+1) = 0 = x^3 -1
const res3 = solveCubic(1, 0, 0, 1);

// This should be
//   x1 = 1
//   x2 = -1
//   x3,4 = -1/2 +/- sqrt(3)/2 i
// for equation (x^2 - 1)(x^2 + x + 1) = 0 = x^4+x^3 -x-1
const res4 = solveQuartic(1, 1, 0, -1, -1);

Notes

• You are free to examine the source code at src folder, and you can test them with command npm test
• To see how to solve the equation of $x^3$ and $x^4$, please read the docs under the folder ./docs/ of the package.
• To make it no-dependency, I wrote a small libary of Complex number operations, all the functions are static, please find them under the src folder if you are interested. Of cource we could import and use other packages like math.js, or complex,js to enpower the complex number calculations.