A tweet-sized, fork-to-play, community-curated collection of JavaScript.
-b ± Math.sqrt(Math.pow(b,2) - 4*a*c)
-------------------------------------
2*a
var solve = function(a,b,c){c=Math.sqrt(b*b-4*a*c);return[(c-b)/(2*a),(-b-c)/(2*a)]};
solve(1,2,-8); // returns [2,-4]| /* Quadratic formula | |
| * -b ± Math.sqrt(Math.pow(b,2) - 4*a*c) | |
| * ------------------------------------- | |
| * 2*a | |
| */ | |
| /* a, b, c are from equation with format: | |
| * ax^2 + bx + c = 0 | |
| */ | |
| function(a,b,c){ | |
| /* save the Math.sqrt(Math.pow(b,2) - 4*a*c) in c | |
| * so, the formula being: | |
| * - b ± c | |
| * ------- | |
| * 2*a | |
| */ | |
| c=Math.sqrt(b*b-4*a*c); | |
| // note the ± after the b variable | |
| return[ | |
| ( c-b)/(2*a), // ± -> positive (note that -b+c => c-b) | |
| (-b-c)/(2*a) // ± -> negative | |
| ] | |
| }; |
| function(a,b,c){c=Math.sqrt(b*b-4*a*c);return[(c-b)/(2*a),(-b-c)/(2*a)]}; |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright (C) 2011 Muhammad Rifqi Priyo Susanto srifqi.github.io | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE FUCK YOU WANT TO. |
| { | |
| "name": "quadraticFormulaSolver", | |
| "description": "Solve and return the results using quadratic formula", | |
| "keywords": [ | |
| "quadratic", | |
| "formula", | |
| "solver", | |
| "math" | |
| ] | |
| } |
| <!DOCTYPE html> | |
| <title>Foo</title> | |
| <div>Expected value: <b>2,-4</b></div> | |
| <div>Actual value: <b id="ret"></b></div> | |
| <script> | |
| // write a small example that shows off the API for your example | |
| // and tests it in one fell swoop. | |
| var myFunction = function(a,b,c){c=Math.sqrt(b*b-4*a*c);return[(c-b)/(2*a),(-b-c)/(2*a)]}; | |
| document.getElementById( "ret" ).innerHTML = myFunction(1,2,-8).join(); | |
| </script> |
Thanks, atk!
Never thought that.