tanh man page

tanh, tanhf, tanhl — hyperbolic tangent function


#include <math.h>

double tanh(double x);

float tanhf(float x);

long double tanhl(long double x);

Link with -lm.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

tanhf(), tanhl():

|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE


These functions return the hyperbolic tangent of x, which is defined mathematically as:

tanh(x) = sinh(x) / cosh(x)

Return Value

On success, these functions return the hyperbolic tangent of x.

If x is a NaN, a NaN is returned.

If x is +0 (-0), +0 (-0) is returned.

If x is positive infinity (negative infinity), +1 (-1) is returned.


No errors occur.


For an explanation of the terms used in this section, see attributes(7).

tanh(), tanhf(), tanhl()Thread safetyMT-Safe

Conforming to

C99, POSIX.1-2001, POSIX.1-2008.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

See Also

acosh(3), asinh(3), atanh(3), cosh(3), ctanh(3), sinh(3)

Referenced By

acosh(3), asinh(3), atanh(3), cosh(3), sinh(3).

Explore man page connections for tanh(3).

tanhf(3) and tanhl(3) are aliases of tanh(3).