In Excel 2010, the Gammaln function has been replaced by the Gammaln.Precise function, which has improved accuracy.
The Excel Gammaln function returns the natural logarithm of the Gamma Function, Γ(n).
The syntax of the function is:
where x is the positive value at which you want to evaluate the function.
The above chart on the right shows the natural logarithm of the Gamma Function.
This gives the result 2.453736571.
Further details and examples of the Excel Gammaln function are provided on the Microsoft Office website.
If you get an error from the Excel Gammaln function this is likely to be one of the following:
|#NUM!||-||Occurs if the supplied value of x is ≤ 0.|
|#VALUE!||-||Occurs if the supplied value of x is non-numeric.|