text: /**
   * Math.js can easily be extended with functions and variables using the
   * `import` function. The function `import` accepts a module name or an object
   * containing functions and variables.
   */
  
  // load math.js
  var math = require('../index');
  
  /**
   * Helper function to output a value in the console. Value will be formatted.
   * @param {*} value
   */
  function print (value) {
    var precision = 14;
    console.log(math.format(value, precision));
  }
  
  /**
   * Define new functions and variables
   */
  math.import({
    myConstant: 42,
    hello: function (name) {
      return 'hello, ' + name + '!';
    }
  });
  
  // defined methods can be used in both JavaScript as well as the parser
  print(math.myConstant * 2);           // 84
  print(math.hello('user'));            // 'hello, user!'
  
  print(math.eval('myConstant + 10'));  // 52
  print(math.eval('hello("user")'));    // 'hello, user!'
  
  
  /**
   * Import the math library numbers.js, https://github.com/sjkaliski/numbers.js
   * The library must be installed first using npm:
   *     npm install numbers
   */
  try {
    // import the numbers.js library into math.js
    math.import('numbers', {wrap: true});
  }
  catch (err) {
    console.log('Warning: to import numbers.js, the library must\n' +
        'be installed first via `npm install numbers`.');
  }
  
  if (math.fibonacci) {
    // calculate fibonacci
    print(math.fibonacci(7));           // 13
    print(math.eval('fibonacci(7)'));   // 13
  }
  
  /**
   * Import the math library numeric.js, http://numericjs.com/
   * The library must be installed first using npm:
   *     npm install numeric
   */
  try {
    // import the numeric.js library into math.js
    math.import('numeric', {wrap: true});
  }
  catch (err) {
    console.log('Warning: to import numeric.js, the library must\n' +
        'be installed first via `npm install numeric`.');
  }
  
  if (math.eig) {
    // calculate eigenvalues of a matrix
    print(math.eval('eig([1, 2; 4, 3])').lambda.x); // [5, -1];
  
    // solve AX = b
    var A = math.eval('[1, 2, 3; 2, -1, 1; 3, 0, -1]');
    var b = [9, 8, 3];
    print(math.solve(A, b)); // [2, -1, 3]
  }
  
  /**
   * By default, the function import does not allow overriding existing functions.
   * Existing functions can be overridden by specifying option `override=true`
   */
  math.import({
    pi: 3.14
  }, {
    override: true
  });
  
  print(math.pi); // returns 3.14 instead of 3.141592653589793
  