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 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).

       allbox; lbw21 lb lb l l l.  Interface Attribute Value T{ tan(), tanf(),
       tanl() T}   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 4.16 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
       https://www.kernel.org/doc/man-pages/.



                                  2017-09-15                            TAN(3)