FNGammareturns the value of the gamma function atx, (x). This function is defined for all real values ofxexcept forxzero or a negative integer, at which points (x) becomes infinite.
Ifxis equal to a positive integer,n, the gamma function is related to the factorial by the relation
This relationship is often used to define a factorial for any real number, by using the definition
(x)
Errors
FNGammacauses an HTBasic error if its argument is not of type REAL or ifx0 andxis an integer.