tanh

Synopsis

$tanh(<number>)

Technical

Returns the hyperbolic tangent of <number>, mathematically sinh(x) / cosh(x), using the system C library and a C double. It is defined for all real inputs and approaches -1 and 1 toward negative and positive infinity. Floating-point rounding can produce exactly those endpoint values for large finite inputs. atanh is the inverse hyperbolic tangent.

The first function word is converted with atof, accepting fractions, scientific notation, and numeric prefixes before trailing text. Nonnumeric input becomes zero. Additional words are ignored; missing input returns the empty string.

Returns

The hyperbolic tangent, formatted with %.50g, rather than limited to six decimal places. Extra printed digits do not imply 50 digits of accuracy. The floating_point_math and floating_point_precision settings do not change this function's calculation or formatting.

Positive infinity returns 1, negative infinity returns -1, and signed zero retains its sign. NaN input ordinarily returns NaN. These special values follow the C library hyperbolic tangent interface.

The shared wrapper clears errno after argument conversion, then returns DOM for a reported domain error, RANGE for a reported range error, or empty for another reported error. It checks errno, not floating-point exception flags; these tokens are not guaranteed for errors reported only through exception flags.

Examples

Approximate examples describe values; returned strings can contain more digits. There are no options or server requirements.

Source

Registration and math wrapper: source/functions.c. Argument conversion and return formatting: include/functions.h.