code: public static double cdf(double val, int v) {
      double x = v / (val * val + v);
      return 1 - (0.5 * BetaDistribution.regularizedIncBeta(x, v * .5, 0.5));
    }
docs: Static version of the CDF of the t-distribution for t &gt; 0
  
  @param val value to evaluate
  @param v degrees of freedom
  @return F(val, v)