text: var assert = require('assert'),
      math = require('../../../index')(),
      approx = require('../../../tools/approx'),
      pi = math.pi,
      complex = math.complex,
      matrix = math.matrix,
      unit = math.unit,
      sec = math.sec;
  
  describe('sec', function() {
    it('should return the secant of a boolean', function () {
      approx.equal(sec(true), 1.85081571768093);
      approx.equal(sec(false), Infinity);
    });
  
    it('should return the secant of a number', function() {
      approx.equal(1 / sec(0), 1);
      approx.equal(1 / sec(pi*1/4), 0.707106781186548);
      approx.equal(1 / sec(pi*1/8), 0.923879532511287);
      approx.equal(1 / sec(pi*2/4), 0);
      approx.equal(1 / sec(pi*3/4), -0.707106781186548);
      approx.equal(1 / sec(pi*4/4), -1);
      approx.equal(1 / sec(pi*5/4), -0.707106781186548);
      approx.equal(1 / sec(pi*6/4), 0);
      approx.equal(1 / sec(pi*7/4), 0.707106781186548);
      approx.equal(1 / sec(pi*8/4), 1);
      approx.equal(1 / sec(pi/4), math.sqrt(2)/2);
  
      approx.equal(math.pow(sec(pi/4), 2), 2);
      approx.equal(sec(0), 1);
      approx.equal(sec(pi), -1);
      approx.equal(sec(-pi), -1);
      approx.equal(math.pow(sec(-pi/4), 2), 2);
      approx.equal(sec(2*pi), 1);
      approx.equal(sec(-2*pi), 1);
    });
  
    it('should return the secant of a bignumber (downgrades to number)', function() {
      approx.equal(sec(math.bignumber(1)), 1.85081571768093);
    });
  
    it('should return the secant of a complex number', function() {
      var re = 0.0416749644111443,
          im = 0.0906111371962376;
      approx.deepEqual(sec(complex('2+3i')), complex(-re, im));
      approx.deepEqual(sec(complex('2-3i')), complex(-re, -im));
      approx.deepEqual(sec(complex('-2+3i')), complex(-re, -im));
      approx.deepEqual(sec(complex('-2-3i')), complex(-re, im));
      approx.deepEqual(sec(complex('i')), complex(0.648054273663885, 0));
      approx.deepEqual(sec(complex('1')), complex(1.85081571768093, 0));
      approx.deepEqual(sec(complex('1+i')), complex(0.498337030555187, 0.591083841721045));
    });
  
    it('should return the secant of an angle', function() {
      approx.equal(sec(unit('45deg')), 1.41421356237310);
      approx.equal(sec(unit('-45deg')), 1.41421356237310);
    });
  
    it('should throw an error if called with an invalid unit', function() {
      assert.throws(function () {sec(unit('5 celsius'))});
    });
  
    it('should throw an error if called with a string', function() {
      assert.throws(function () {sec('string')});
    });
  
    var sec123 = [1.85081571768093, -2.40299796172238, -1.01010866590799];
  
    it('should return the secant of each element of an array', function() {
      approx.deepEqual(sec([1,2,3]), sec123);
    });
  
    it('should return the secant of each element of a matrix', function() {
      approx.deepEqual(sec(matrix([1,2,3])), matrix(sec123));
    });
  
  });