Re: Calculation assistance.. :)

Eric ... I LOVE YOU... Thanks -- Stephen Johnson c | eh The Lone Coder http://www.thelonecoder.com continuing the struggle against bad code http://www.fortheloveofgeeks.com I¹m a geek and I¹m OK! -- > From: Eric Gorr <mailist@ericgorr.net> > Date: Fri, 19 Sep 2008 16:13:49 -0400 > To: Stephen Johnson <stephen@thelonecoder.com> > Cc: PHP list - not junk <php-general@lists.php.net> > Subject: Re: [PHP] Calculation assistance.. :) > > You originally had: > > $nPrincipal * ( $nMonthlyInterest / (1 - (1 + $nMonthlyInterest) ^ - > $iMonths)) > > which, translate to in PHP > > $nPrincipal * ( $nMonthlyInterest / (1 - pow( ( 1 + > $nMonthlyInterest ), -$iMonths ) ) ) > > > > > On Sep 19, 2008, at 3:48 PM, Stephen Johnson wrote: > >> Right ... But that is producing even funkier results... >> >> doing pow( (1-(1+$nMonthlyInterest)) , ($iMonths*-1) ) ; >> >> Gives me : >> >> 4.2502451372964E-35 = 25000 * (0.0010416666666667 / 6.1270975733019E >> +35); >> >> >>> From: Eric Gorr <mailist@ericgorr.net> >>> >>> I believe what you are looking is: >>> >>> http://us2.php.net/manual/en/function.pow.php >>> >>> number pow ( number $base , number $exp ) >>> Returns base raised to the power of exp >>> >>> >>> >>> On Sep 19, 2008, at 3:34 PM, Stephen Johnson wrote: >>> >>>> OK.. Math is NOT my forte ... >>>> >>>> I am converting a site from ASP to PHP ... And this calc is in the >>>> ASP Code >>>> : >>>> >>>> $nMonthlyInterest = $nRate / (12 * 100) >>>> >>>> //' Calculate monthly payment >>>> $nPayment = $nPrincipal * ( $nMonthlyInterest / (1 - (1 + >>>> $nMonthlyInterest) ^ -$iMonths)) >>>> >>>> Which then gives me in PHP >>>> 0.0010416666666667 = 1.25 / (12 * 100); >>>> -2.1701388888889 = 25000 * ( 0.0010416666666667 / (1 - (1 + >>>> 0.0010416666666667) ^ -12)) :: >>>> >>>> ^ is the problem ... >>>> >>>> The solution SHOULD be 2,097.47 ... Not ­2.17 >>>> >>>> Would be willing to help correct this and make it valid in PHP? >>> >> >> >