1.\" Copyright (c) 1985, 1991 Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)sqrt.3 6.4 (Berkeley) 5/6/91 33.\" $FreeBSD$ 34.\" 35.Dd May 6, 1991 36.Dt SQRT 3 37.Os 38.Sh NAME 39.Nm cbrt , 40.Nm cbrtf , 41.Nm sqrt , 42.Nm sqrtf 43.Nd cube root and square root functions 44.Sh LIBRARY 45.Lb libm 46.Sh SYNOPSIS 47.In math.h 48.Ft double 49.Fn cbrt "double x" 50.Ft float 51.Fn cbrtf "float x" 52.Ft double 53.Fn sqrt "double x" 54.Ft float 55.Fn sqrtf "float x" 56.Sh DESCRIPTION 57The 58.Fn cbrt 59and the 60.Fn cbrtf 61functions compute 62the cube root of 63.Ar x . 64.Pp 65The 66.Fn sqrt 67and the 68.Fn sqrtf 69functions compute the 70non-negative square root of x. 71.Sh RETURN VALUES 72The 73.Fn cbrt 74and the 75.Fn cbrtf 76functions return the requested cube root. 77The 78.Fn sqrt 79and the 80.Fn sqrtf 81functions return the requested square root 82unless an error occurs. 83On the 84.Tn VAX 85or 86.Tn Tahoe 87processor an attempt to take the 88.Fn sqrt 89of negative 90.Fa x 91causes an error; in this event, 92the global variable 93.Va errno 94is set to 95.Er EDOM 96and a reserved operand fault is generated. 97.Sh ERROR (due to Roundoff etc.) 98The 99.Fn cbrt 100function 101is accurate to within 0.7 102.Em ulps . 103.Pp 104The 105.Fn sqrt 106function on a 107.Tn VAX 108is accurate to within 0.501 109.Em ulps . 110Sqrt on a machine that conforms to 111.Tn IEEE 112754 is correctly rounded 113in accordance with the rounding mode in force; the error is less than 114half an 115.Em ulp 116in the default mode (round\-to\-nearest). 117An 118.Em ulp 119is one 120.Em U Ns nit 121in the 122.Em L Ns ast 123.Em P Ns lace 124carried. 125.Sh SEE ALSO 126.Xr math 3 127.Sh STANDARDS 128The 129.Fn sqrt 130function conforms to 131.St -isoC . 132.Sh HISTORY 133The 134.Fn cbrt 135function appeared in 136.Bx 4.3 . 137