betaIncomplete function

double betaIncomplete (double a, double b, double x)

Returns the lower incomplete (unregularized) beta function B(a,b,x) = int(t^(a-1)*(1-t)^(b-1),t=0..x) for real a > 0, b > 0, 1 >= x >= 0.

Implementation

double betaIncomplete(double a, double b, double x) =>
    betaRegularized(a, b, x) * beta(a, b);