mathjs/src/function/trigonometry/asin.js

'use strict'

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

function factory (type, config, load, typed) {
  /**
   * Calculate the inverse sine of a value.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.asin(x)
   *
   * Examples:
   *
   *    math.asin(0.5)           // returns number 0.5235987755982989
   *    math.asin(math.sin(1.5)) // returns number ~1.5
   *
   *    math.asin(2)             // returns Complex 1.5707963267948966 -1.3169578969248166 i
   *
   * See also:
   *
   *    sin, atan, acos
   *
   * @param {number | BigNumber | Complex | Array | Matrix} x   Function input
   * @return {number | BigNumber | Complex | Array | Matrix} The arc sine of x
   */
  const asin = typed('asin', {
    'number': function (x) {
      if ((x >= -1 && x <= 1) || config.predictable) {
        return Math.asin(x)
      } else {
        return new type.Complex(x, 0).asin()
      }
    },

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

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

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

  asin.toTex = { 1: `\\sin^{-1}\\left(\${args[0]}\\right)` }

  return asin
}

exports.name = 'asin'
exports.factory = factory