static public double ppmt(double r, int per, int nper, double pv, double fv, int type) {return pmt(r, nper, pv, fv, type) - ipmt(r, per, nper, pv, fv, type);}
static public double PPMT(double r, int per, int nper, double pv, double fv, int type){return PMT(r, nper, pv, fv, type) - IPMT(r, per, nper, pv, fv, type);}