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68k Calculator Basic => TI-BASIC
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sean

Newbie

Joined: 18 Jan 2008
Posts: 6

 Posted: 18 Jan 2008 11:39:43 pm    Post subject: Hey, I have the Finance pkg. from TI, but there is no Net present value, or future val. is there an add in, or app that I can use to add advanced finance functions? Thanks.
simonzack

Joined: 25 Dec 2007
Posts: 71

 Posted: 19 Jan 2008 12:03:08 am    Post subject: I'm not too familiar with that package, but if you can't really find any, you need to look for programs besides TI itself, like in the TIcalc.org archives
sean

Newbie

Joined: 18 Jan 2008
Posts: 6

 Posted: 19 Jan 2008 10:20:43 am    Post subject: Yes, I've looked there, I have seen a few people complain about the lack of NPV, but no program to use. I have no idea how to write one, but it may be worth learning, it is not that complicated a formula, but can be long. What kills me is it is available on the ti83/84. I bought the 89 because I expected the most options and functions. Right now I carry two calculators, financial, and graphing, a bit of a pain.
DarkerLine
ceci n'est pas une |

Super Elite (Last Title)

Joined: 04 Nov 2003
Posts: 8328

 Posted: 19 Jan 2008 11:12:25 am    Post subject: Here's a function that will calculate npv(): Define npv(i,cf0,cflist)=cf0+Σ(cflist[j](1+i)^-j,j,1,dim(cflist)) This does not have the frequency list functionality of the TI-83 Plus npv( command. If you want to use frequency lists, you could do this (which is a good bit more complicated): npv_f(i,cf0,cflist,freq) Func Local cumfreq augment({0},cumSum(freq))->cumfreq Return cf0+Σ(cflist[j](1+i)^-cumfreq[j](1-(1+i)^-freq[j])/i,j,1,dim(cflist)) EndFuncLast edited by Guest on 30 Aug 2010 08:21:46 pm; edited 1 time in total
thornahawk
μολών λαβέ

Active Member

Joined: 27 Mar 2005
Posts: 569

 Posted: 19 Jan 2008 11:22:21 am    Post subject: Shouldn't that be (1+i)^-cumfreq[j], if we're going to follow the formula in the TI-83+ manual? thornahawk
DarkerLine
ceci n'est pas une |

Super Elite (Last Title)

Joined: 04 Nov 2003
Posts: 8328

 Posted: 19 Jan 2008 11:46:47 am    Post subject: It should... typo! And there was a point at which I invented a magic syntax for cumSum( that did what I wanted it to do, rather than what it's supposed to do. Also fixed.Last edited by Guest on 19 Jan 2008 11:50:27 am; edited 1 time in total
sean

Newbie

Joined: 18 Jan 2008
Posts: 6

 Posted: 19 Jan 2008 12:58:18 pm    Post subject: DarkerLine wrote:Here's a function that will calculate npv(): Define npv(i,cf0,cflist)=cf0+Σ(cflist[j](1+i)^-j,j,1,dim(cflist)) This does not have the frequency list functionality of the TI-83 Plus npv( command. If you want to use frequency lists, you could do this (which is a good bit more complicated): npv_f(i,cf0,cflist,freq) Func Local cumfreq augment({0},cumSum(freq))->cumfreq Return cf0+Σ(cflist[j](1+i)^-cumfreq[j](1-(1+i)^-freq[j])/i,j,1,dim(cflist)) EndFunc [post="119073"]<{POST_SNAPBACK}>[/post] Hi, thanks for the reply. Does the cumfreq go in the original function? I have put it in both ways, with it I get data type error, without It just displays what I have typed in. i.e. finance\npv(10,0,200) returns the same thing with Done under it. I am a total Noob in this, so please don't hesitate to talk at a 5 yr old level, and thank you for your time.Last edited by Guest on 30 Aug 2010 08:22:06 pm; edited 1 time in total
DarkerLine
ceci n'est pas une |

Super Elite (Last Title)

Joined: 04 Nov 2003
Posts: 8328

 Posted: 19 Jan 2008 01:14:57 pm    Post subject: Go to the finance folder, and enter the line that starts with "Define..." on the homescreen, this will create the function npv(. It should not have a "cumfreq". Note, however, that the third argument is a list. So you would enter finance\npv(10,0,{200}). Or, you can use a list of several values. You can also define the function using the program editor, in which case you would enter this: npv(i,cf0,cflist) :cf0+Σ(cflist[j](1+i)^-j,j,1,dim(cflist)) Or, more formally: npv(i,cf0,cflist) :Func :Return cf0+Σ(cflist[j](1+i)^-j,j,1,dim(cflist)) :EndFunc The second function I gave, npv_f, should be entered through the program editor.Last edited by Guest on 30 Aug 2010 08:21:30 pm; edited 1 time in total
sean

Newbie

Joined: 18 Jan 2008
Posts: 6

 Posted: 19 Jan 2008 01:27:09 pm    Post subject: Sucess!!! Thank you. results match the finance calc. No more carrying two calcs. Hmm, what else can I add to this thing? Thanks again for the help.
sean

Newbie

Joined: 18 Jan 2008
Posts: 6

 Posted: 19 Jan 2008 01:28:21 pm    Post subject: of course I just killed an hour and a half of HW time...
sean

Newbie

Joined: 18 Jan 2008
Posts: 6

 Posted: 19 Jan 2008 01:32:20 pm    Post subject: this is sweeeet, I can see all fin. variables on the screen and do what ifs.
thornahawk
μολών λαβέ

Active Member

Joined: 27 Mar 2005
Posts: 569

 Posted: 22 Jan 2008 02:08:47 am    Post subject: You might want to look for the book "Financial Numerical Recipes" if you're interested in extending the functionality of your TI 89 for finance-related calculations. thornahawk
jack upton

Newbie

Joined: 30 Apr 2008
Posts: 1

 Posted: 30 Apr 2008 07:19:24 am    Post subject: For NPV, and many other financial calculations on the 83/84, check out Accounting, Business, and Finance Made Easy: http://www.ti89.com/abfme/index_abfme.htm
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