tan - Man Page
tangent function
Library
Math library (libm, -lm)
Synopsis
#include <math.h> double tan(double x); float tanf(float x); long double tanl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
tanf(), tanl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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 |
Standards
C11, POSIX.1-2008.
History
C99, POSIX.1-2001.
The variant returning double also conforms to SVr4, 4.3BSD, C89.
Bugs
Before glibc 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)
Referenced By
acos(3), asin(3), atan(3), atan2(3), cos(3), sin(3), sincos(3).
The man pages tanf(3) and tanl(3) are aliases of tan(3).