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 versions <= 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)

COLOPHON

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       information   about   reporting   bugs,   and   the  latest  version  of  this  page,  can  be  found  at
       https://www.kernel.org/doc/man-pages/.

                                                   2017-09-15                                             TAN(3)