2011-03-18 16:52:16 +01:00
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.\" Copyright (c) 1991 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" from: @(#)tanh.3 5.1 (Berkeley) 5/2/91
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2013-12-06 12:04:52 +01:00
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.\" $NetBSD: tanh.3,v 1.15 2011/11/17 23:46:32 wiz Exp $
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2011-03-18 16:52:16 +01:00
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.\"
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2013-12-06 12:04:52 +01:00
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.Dd September 18, 2011
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2011-03-18 16:52:16 +01:00
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.Dt TANH 3
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.Os
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.Sh NAME
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.Nm tanh ,
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.Nm tanhf
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.Nd hyperbolic tangent function
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.Sh LIBRARY
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.Lb libm
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.Sh SYNOPSIS
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.In math.h
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.Ft double
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.Fn tanh "double x"
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.Ft float
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.Fn tanhf "float x"
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.Sh DESCRIPTION
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The
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.Fn tanh
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and
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.Fn tanhf
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functions compute the hyperbolic tangent of
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.Fa x .
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For a discussion of error due to roundoff, see
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.Xr math 3 .
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.Sh RETURN VALUES
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2013-12-06 12:04:52 +01:00
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Upon successful completion,
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these functions return the hyperbolic tangent value.
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The following may also occur:
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.Bl -enum -offset indent
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.It
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If
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.Fa x
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is \*(Pm 0,
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.Fa x
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is returned.
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.It
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If
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.Fa x
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is \*(Na, a \*(Na is returned.
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.It
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If
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.Fa x
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is positive infinity, a value 1 is returned;
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if
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.Fa x
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is negative infinity, -1 is returned.
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.It
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If
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.Fa x
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is subnormal, a range error can occur and
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.Fa x
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is returned.
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.El
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2011-03-18 16:52:16 +01:00
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.Sh SEE ALSO
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.Xr acos 3 ,
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.Xr asin 3 ,
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.Xr atan 3 ,
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.Xr atan2 3 ,
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.Xr cos 3 ,
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.Xr cosh 3 ,
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.Xr math 3 ,
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.Xr sin 3 ,
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.Xr sinh 3 ,
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.Xr tan 3
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.Sh STANDARDS
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2013-12-06 12:04:52 +01:00
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The described functions conform to
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.St -isoC-99 .
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