The Excel GAMMALN Function
GAMMALN and GAMMALN.PRECISE Functions
In Excel 2010, the Gammaln function has been replaced by the Gammaln.Precise function, which has improved accuracy.
Although it has been replaced, the Gammaln function is still available in Excel 2010, to allow compatibility with earlier versions of Excel.
Function Description
The Excel Gammaln function returns the natural logarithm of the Gamma Function, Γ(n).
The syntax of the function is:
GAMMALN( x )
where x is the positive value at which you want to evaluate the function.
Gammaln Function Example
Natural Logarithm of the Gamma Function
The above chart on the right shows the natural logarithm of the Gamma Function.
If you want to calculate the value of this function at x = 4.5, this can be done using the Excel Gammaln function, as follows:
=GAMMALN( 4.5 )
This gives the result 2.453736571.
For further details and examples of the Excel Gammaln function, see the Microsoft Office website.
Gammaln Function Errors
If you get an error from the Excel Gammaln function this is likely to be one of the following:
Common Errors
| #NUM! | - | Occurs if the supplied value of x is ≤ 0. |
| #VALUE! | - | Occurs if the supplied value of x is non-numeric. |