**tan**

**TAN(3)** Linux Programmer's Manual **TAN(3)**
NAME
tan, tanf, tanl - tangent function
SYNOPSIS
#include <math.h>
double tan(double x);
float tanf(float x);
long double tanl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see **feature_test_macros(7)**):
tanf(), tanl():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99
DESCRIPTION
These functions return the tangent of x, where x is given in radians.
RETURN VALUE
On success, these functions return the tangent of x.
If x is a NaN, a NaN is returned.
If x is positive infinity or negative infinity, a domain error occurs,
and a NaN is returned.
If the correct result would overflow, a range error occurs, and the
functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively, with
the mathematically correct sign.
ERRORS
See **math_error(7)** for information on how to determine whether an error
has occurred when calling these functions.
The following errors can occur:
Domain error: x is an infinity
errno is set to EDOM (but see BUGS). An invalid floating-point
exception (FE_INVALID) is raised.
Range error: result overflow
An overflow floating-point exception (FE_OVERFLOW) is raised.
ATTRIBUTES
For an explanation of the terms used in this section, see
**attributes(7)**.
+----------------------+---------------+---------+
|Interface | Attribute | Value |
+----------------------+---------------+---------+
|tan(), tanf(), tanl() | Thread safety | MT-Safe |
+----------------------+---------------+---------+
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD, C89.
BUGS
Before version 2.10, the glibc implementation did not set errno to EDOM
when a domain error occurred.
SEE ALSO
**acos(3)**, **asin(3)**, **atan(3)**, **atan2(3)**, **cos(3)**, **ctan(3)**, **sin(3)**
COLOPHON
This page is part of release 4.04 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
http://www.kernel.org/doc/man-pages/.
2015-04-19 **TAN(3)**

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