JavaScript封装了自己的函数库，下面来看看最常用的数学运算函数，以及封装使用的math.js工具包。

Math基本属性和方法

MathJs

An extensive math library for JavaScript and Node.js

Math.js is an extensive math library for JavaScript and Node.js.It features a flexible expression parser and offers an integrated solutionto work with numbers, big numbers, complex numbers, units, and matrices.Powerful and easy to use.

Features

Supports numbers, big numbers, fractions, complex numbers, units, strings, arrays, and matrices.
Is compatible with JavaScript’s built-in Math library.
Contains a flexible expression parser.
Supports chained operations.
Comes with a large set of built-in functions and constants.
Has no dependencies. Runs on any JavaScript engine.
Is easily extensible.
Open source.

JS工具包引用示例：


<!DOCTYPE HTML>
<html>
<head>
  <script src="math.js" type="text/javascript"></script>
</head>
<body>
  <script type="text/javascript">
    // use math.js
    math.sqrt(-4); // 2i
  </script>
</body>
</html>

更多函数示例：


// functions and constants
math.round(math.e, 3);            // 2.718
math.atan2(3, -3) / math.pi;      // 0.75
math.log(10000, 10);              // 4
math.sqrt(-4);                    // 2i
math.pow([[-1, 2], [3, 1]], 2);
     // [[7, 0], [0, 7]]
 
// expressions
math.eval('1.2 * (2 + 4.5)');     // 7.8
math.eval('5.08 cm to inch');     // 2 inch
math.eval('sin(45 deg) ^ 2');     // 0.5
math.eval('9 / 3 + 2i');          // 3 + 2i
math.eval('det([-1, 2; 3, 1])');  // -7
 
// chaining
math.chain(3)
    .add(4)
    .multiply(2)
    .done(); // 14