text: public static double pmt(double r, double n, double p, double f, bool t){double retval = 0;if (r == 0){retval = -1 * (f + p) / n;}else{double r1 = r + 1;retval = (f + p * Math.Pow(r1, n)) * r/((t ? r1 : 1) * (1 - Math.Pow(r1, n)));}return retval;}