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():
           _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 │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

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)

                                                                               2021-03-22                                                                         TAN(3)