mathjs/src/function/trigonometry/acos.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

import { factory } from '../../utils/factory'
import { deepMap } from '../../utils/collection'

const name = 'acos'
const dependencies = ['typed', 'config', 'Complex']

export const createAcos = /* #__PURE__ */ factory(name, dependencies, ({ typed, config, Complex }) => {
  /**
   * Calculate the inverse cosine of a value.
   *
   * For matrices, the function is evaluated element wise.
   *
   * Syntax:
   *
   *    math.acos(x)
   *
   * Examples:
   *
   *    math.acos(0.5)           // returns number 1.0471975511965979
   *    math.acos(math.cos(1.5)) // returns number 1.5
   *
   *    math.acos(2)             // returns Complex 0 + 1.3169578969248166 i
   *
   * See also:
   *
   *    cos, atan, asin
   *
   * @param {number | BigNumber | Complex | Array | Matrix} x  Function input
   * @return {number | BigNumber | Complex | Array | Matrix} The arc cosine of x
   */
  const acos = typed(name, {
    number: function (x) {
      if ((x >= -1 && x <= 1) || config.predictable) {
        return Math.acos(x)
      } else {
        return new Complex(x, 0).acos()
      }
    },

    Complex: function (x) {
      return x.acos()
    },

    BigNumber: function (x) {
      return x.acos()
    },

    'Array | Matrix': function (x) {
      return deepMap(x, acos)
    }
  })

  return acos
})