ahavercos.js (1267B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var acos = require( './../../../../base/special/acos' ); 24 var sqrt = require( './../../../../base/special/sqrt' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the inverse half-value versed cosine. 31 * 32 * @param {number} x - input value 33 * @returns {number} inverse half-value versed cosine 34 * 35 * @example 36 * var v = ahavercos( 0.0 ); 37 * // returns ~3.1416 38 * 39 * @example 40 * var v = ahavercos( 1.0 ); 41 * // returns 0.0 42 * 43 * @example 44 * var v = ahavercos( 0.5 ); 45 * // returns ~1.5708 46 * 47 * @example 48 * var v = ahavercos( NaN ); 49 * // returns NaN 50 */ 51 function ahavercos( x ) { 52 return 2.0 * acos( sqrt( x ) ); 53 } 54 55 56 // EXPORTS // 57 58 module.exports = ahavercos;