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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():

_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99

Description

The tan() function returns 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

Multithreading (see pthreads(7) )

The tan(), tanf(), and tanl() functions are thread-safe.

Conforming to

C99, POSIX.1-2001. 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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