gamma_cdf(A;B;X)
  
  Returns the gamma cumulative distribution function with shape
      parameter A, rate parameter B, and value
      X.
Syntax
gamma_cdf(A;B;X)
    Input
| Argument | Type | Description | 
|---|---|---|
A | 
            integer or decimal | A scalar value or the name of a column The shape parameter  | 
          
B | 
            integer or decimal | A scalar value or the name of a column The rate parameter  | 
          
| X | integer or decimal | A scalar value or the name of a column The value to evaluate with. X must be greater than 0.  | 
          
Return Value
Returns the gamma cumulative distribution function with shape parameter A,
        rate parameter B, and value X.
If any argument is N/A, the result is N/A.
