/***************************************************************************
* Copyright (C) 2007, Paul Lutus *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
ratprint : false;
solve_for_var(eq,v) := ev(rhs(solve(eq,v)[1]),fullratsimp,factor);
/* print currency amounts */
pcurr(s,x) := printf(true,"~a: ~16,2f~%",s,float(x));
/* the "meta-equation" */
eq:fv=((pb*ir+1)*pmt-(ir+1)^np*((pb*ir*pmt)+pmt+ir*pv))/ir;
fpv(fv,np,pmt,ir,pb) := solve_for_var(eq,pv);
ffv(pv,np,pmt,ir,pb) := solve_for_var(eq,fv);
fnp(fv,pv,pmt,ir,pb) := solve_for_var(eq,np);
fpmt(fv,pv,np,ir,pb) := solve_for_var(eq,pmt);
fir(fv,pv,np,pmt,pb) := solve_for_var(eq,ir); /* this case isn't really soluble */
pb:0; /* payment at end */
display(fpv(fv,np,pmt,ir,pb));
display(ffv(pv,np,pmt,ir,pb));
display(fnp(fv,pv,pmt,ir,pb));
display(fpmt(fv,pv,np,ir,pb));
display(fir(fv,pv,np,pmt,pb)); /* too bad this isn't real */
/* show examples of payment at beginning and end */
pcurr("FV, Payment at beginning", ffv(0,120,-100,0.01,0));
pcurr("FV, Payment at end ",ffv(0,120,-100,0.01,1));