tan(3) Library Functions Manual tan(3) NAME tan, tanf, tanl - tangent function LIBRARY Math library (libm, -lm) SYNOPSIS #include 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) Linux man-pages 6.8 2024-05-02 tan(3)