mathjs/src/function/trigonometry/tan.js

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

'use strict'

const deepMap = require('../../utils/collection/deepMap')

function factory (type, config, load, typed) {
  /**
   * Calculate the tangent of a value. `tan(x)` is equal to `sin(x) / cos(x)`.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.tan(x)
   *
   * Examples:
   *
   *    math.tan(0.5)                    // returns number 0.5463024898437905
   *    math.sin(0.5) / math.cos(0.5)    // returns number 0.5463024898437905
   *    math.tan(math.pi / 4)            // returns number 1
   *    math.tan(math.unit(45, 'deg'))   // returns number 1
   *
   * See also:
   *
   *    atan, sin, cos
   *
   * @param {number | BigNumber | Complex | Unit | Array | Matrix} x  Function input
   * @return {number | BigNumber | Complex | Array | Matrix} Tangent of x
   */
  const tan = typed('tan', {
    'number': Math.tan,

    'Complex': function (x) {
      return x.tan()
    },

    'BigNumber': function (x) {
      return x.tan()
    },

    'Unit': function (x) {
      if (!x.hasBase(type.Unit.BASE_UNITS.ANGLE)) {
        throw new TypeError('Unit in function tan is no angle')
      }
      return tan(x.value)
    },

    'Array | Matrix': function (x) {
      // deep map collection, skip zeros since tan(0) = 0
      return deepMap(x, tan, true)
    }
  })

  tan.toTex = { 1: `\\tan\\left(\${args[0]}\\right)` }

  return tan
}

exports.name = 'tan'
exports.factory = factory