tan

Synopsis

$tan(<number>)

Technical

Returns the tangent of the angle given in radians, using the system C library and a C double. atan returns a principal inverse angle.

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 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.

The wrapper clears errno after argument conversion, then returns DOM for a library-reported domain error, RANGE for a reported range error, or empty for another reported error. It checks errno, not floating-point exception flags. Infinite input ordinarily produces a domain error and NaN; EPIC returns DOM if reported through errno, otherwise it can return a NaN string. NaN input ordinarily returns NaN. See the C library tangent interface.

Restrictions

Tangent has mathematical poles at odd multiples of π/2. A decimal approximation to such an angle is a finite floating-point value, so it can return a large finite result rather than an error or infinity. Accuracy can suffer near these poles or for very large angles; do not use a DOM or RANGE result as the only test for proximity to a pole.

Examples

Approximate examples describe values; the 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.