121 lines
3.1 KiB
Groff
121 lines
3.1 KiB
Groff
.\" Copyright (c) 1985, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)sqrt.3 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt SQRT 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm cbrt ,
|
|
.Nm sqrt
|
|
.Nd cube root and square root functions
|
|
.Sh SYNOPSIS
|
|
.Fd #include <math.h>
|
|
.Ft double
|
|
.Fn cbrt "double x"
|
|
.Ft double
|
|
.Fn sqrt "double x"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn cbrt
|
|
function computes
|
|
the cube root of
|
|
.Ar x .
|
|
.Pp
|
|
The
|
|
.Fn sqrt
|
|
computes the
|
|
non-negative square root of x.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn cbrt
|
|
function returns the requested cube root.
|
|
The
|
|
.Fn sqrt
|
|
function returns the requested square root
|
|
unless an error occurs.
|
|
On the
|
|
.Tn VAX
|
|
or
|
|
.Tn Tahoe
|
|
processor an attempt to take the
|
|
.Fn sqrt
|
|
of negative
|
|
.Fa x
|
|
causes an error; in this event,
|
|
the global variable
|
|
.Va errno
|
|
is set to
|
|
.Dv EDOM
|
|
and a reserved operand fault is generated.
|
|
.Sh ERROR (due to Roundoff etc.)
|
|
The
|
|
.Fn cbrt
|
|
function
|
|
is accurate to within 0.7
|
|
.Em ulps .
|
|
.Pp
|
|
The
|
|
.Fn sqrt
|
|
function on a
|
|
.Tn VAX
|
|
is accurate to within 0.501
|
|
.Em ulps .
|
|
Sqrt on a machine that conforms to
|
|
.Tn IEEE
|
|
754 is correctly rounded
|
|
in accordance with the rounding mode in force; the error is less than
|
|
half an
|
|
.Em ulp
|
|
in the default mode (round\-to\-nearest).
|
|
An
|
|
.Em ulp
|
|
is one
|
|
.Em U Ns nit
|
|
in the
|
|
.Em L Ns ast
|
|
.Em P Ns lace
|
|
carried.
|
|
.Sh SEE ALSO
|
|
.Xr infnan 3 ,
|
|
.Xr math 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Nm sqrt
|
|
function conforms to
|
|
.St -ansiC .
|
|
.Sh HISTORY
|
|
The
|
|
.Nm cbrt
|
|
function appeared in
|
|
.Bx 4.3 .
|