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fea681da | 1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
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2 | .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk |
3 | .\" <mtk.manpages@gmail.com> | |
fea681da | 4 | .\" |
93015253 | 5 | .\" %%%LICENSE_START(VERBATIM) |
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6 | .\" Permission is granted to make and distribute verbatim copies of this |
7 | .\" manual provided the copyright notice and this permission notice are | |
8 | .\" preserved on all copies. | |
9 | .\" | |
10 | .\" Permission is granted to copy and distribute modified versions of this | |
11 | .\" manual under the conditions for verbatim copying, provided that the | |
12 | .\" entire resulting derived work is distributed under the terms of a | |
13 | .\" permission notice identical to this one. | |
c13182ef | 14 | .\" |
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15 | .\" Since the Linux kernel and libraries are constantly changing, this |
16 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
17 | .\" responsibility for errors or omissions, or for damages resulting from | |
18 | .\" the use of the information contained herein. The author(s) may not | |
19 | .\" have taken the same level of care in the production of this manual, | |
20 | .\" which is licensed free of charge, as they might when working | |
21 | .\" professionally. | |
c13182ef | 22 | .\" |
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23 | .\" Formatted or processed versions of this manual, if unaccompanied by |
24 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 25 | .\" %%%LICENSE_END |
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26 | .\" |
27 | .\" References consulted: | |
28 | .\" Linux libc source code | |
29 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
30 | .\" 386BSD man pages | |
31 | .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) | |
32 | .\" Modified 2002-07-27 by Walter Harms | |
33 | .\" (walter.harms@informatik.uni-oldenburg.de) | |
34 | .\" | |
c73595c2 | 35 | .TH TANH 3 2015-04-19 "" "Linux Programmer's Manual" |
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36 | .SH NAME |
37 | tanh, tanhf, tanhl \- hyperbolic tangent function | |
38 | .SH SYNOPSIS | |
39 | .nf | |
40 | .B #include <math.h> | |
41 | .sp | |
42 | .BI "double tanh(double " x ); | |
d39541ec | 43 | .br |
fea681da | 44 | .BI "float tanhf(float " x ); |
d39541ec | 45 | .br |
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46 | .BI "long double tanhl(long double " x ); |
47 | .fi | |
48 | .sp | |
20c58d70 | 49 | Link with \fI\-lm\fP. |
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50 | .sp |
51 | .in -4n | |
52 | Feature Test Macro Requirements for glibc (see | |
53 | .BR feature_test_macros (7)): | |
54 | .in | |
55 | .sp | |
56 | .ad l | |
57 | .BR tanhf (), | |
58 | .BR tanhl (): | |
b90c43a8 | 59 | .RS 4 |
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60 | _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE || |
61 | _POSIX_C_SOURCE\ >=\ 200112L; | |
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62 | .br |
63 | or | |
3c0484a7 | 64 | .I cc\ -std=c99 |
b90c43a8 | 65 | .RE |
b90c43a8 | 66 | .ad |
fea681da | 67 | .SH DESCRIPTION |
5600f73a | 68 | These functions return the hyperbolic tangent of |
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69 | .IR x , |
70 | which | |
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71 | is defined mathematically as: |
72 | .nf | |
73 | ||
74 | tanh(x) = sinh(x) / cosh(x) | |
494fc522 | 75 | .fi |
47297adb | 76 | .SH RETURN VALUE |
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77 | On success, these functions return the hyperbolic tangent of |
78 | .IR x . | |
79 | ||
80 | If | |
81 | .I x | |
82 | is a NaN, a NaN is returned. | |
83 | ||
84 | If | |
85 | .I x | |
86 | is +0 (\-0), +0 (\-0) is returned. | |
87 | ||
88 | If | |
89 | .I x | |
90 | is positive infinity (negative infinity), | |
91 | +1 (\-1) is returned. | |
92 | .\" | |
385cf745 | 93 | .\" POSIX.1-2001 documents an optional range error (underflow) |
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94 | .\" for subnormal x; |
95 | .\" glibc 2.8 does not do this. | |
96 | .SH ERRORS | |
97 | No errors occur. | |
38d62724 | 98 | .SH ATTRIBUTES |
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99 | For an explanation of the terms used in this section, see |
100 | .BR attributes (7). | |
101 | .TS | |
102 | allbox; | |
103 | lbw24 lb lb | |
104 | l l l. | |
105 | Interface Attribute Value | |
106 | T{ | |
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107 | .BR tanh (), |
108 | .BR tanhf (), | |
38d62724 | 109 | .BR tanhl () |
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110 | T} Thread safety MT-Safe |
111 | .TE | |
47297adb | 112 | .SH CONFORMING TO |
9a74e018 | 113 | C99, POSIX.1-2001, POSIX.1-2008. |
e05e3635 | 114 | |
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115 | The variant returning |
116 | .I double | |
117 | also conforms to | |
68e1685c | 118 | SVr4, 4.3BSD, C89. |
47297adb | 119 | .SH SEE ALSO |
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120 | .BR acosh (3), |
121 | .BR asinh (3), | |
122 | .BR atanh (3), | |
123 | .BR cosh (3), | |
36268806 | 124 | .BR ctanh (3), |
fea681da | 125 | .BR sinh (3) |