Beta Function (Not in Base Package)

The beta function B(w,z) is defined by gamma (w)*gamma(z)/gamma(w + z) as shown below.

The calculation of B(w,z) uses the Gamma Function VI.

z is any real number.
w is any real number.
beta(w,z) is the result of the calculation of B(w,z) for the given values of w and z.

Note  B(w,z) is undefined if w or z is a non-positive integer.