public static double PV(double rate, double nPer, double pmt, double fv = 0.0, DueDatePeriod period = DueDatePeriod.EndOfPeriod)
{
double pv;
if (rate == 0.0)
{
pv = -fv - pmt * nPer;
}
else
{
double factor = period == DueDatePeriod.EndOfPeriod ? 1.0 : 1.0 + rate;
double pow = Math.Pow(1.0 + rate, nPer);
pv = -(fv + pmt * factor * ((pow - 1.0) / rate)) / pow;
}
return(pv);
}
private static double FV(double rate, double nPer, double pmt, double pv = 0.0, DueDatePeriod period = DueDatePeriod.EndOfPeriod)
{
double fv;
if (rate == 0.0)
{
fv = -pv - pmt * nPer;
}
else
{
double factor = period == DueDatePeriod.EndOfPeriod ? 1.0 : 1.0 + rate;
double pow = Math.Pow(1.0 + rate, nPer);
fv = -pv * pow - pmt / rate * factor * (pow - 1.0);
}
return(fv);
}
