Incomplete Gamma Function (Not in Base Package)

Evaluates the incomplete gamma function for any real number x and the positive real number a as defined by the following for a > 0.

Details

x is any real number.
a is a positive real number.
incomplete gamma (a,x) is the result of the calculation of P(a,x) for the given values of a and x.
error returns any error or warning condition from the VI.

Incomplete Gamma Function Details

The integral in the definition of P(a, x) can approximately be derived by the following equation.

The following diagram shows the incomplete gamma functions with a = 1, 2, 3, and 4 from top to bottom.