Login [Register]
Don't have an account? Register now to chat, post, use our tools, and much more.
This is an archived, read-only copy of the United-TI subforum , including posts and topic from May 2003 to April 2012. If you would like to discuss any of the topics in this forum, you can visit Cemetech's TI-BASIC subforum. Some of these topics may also be directly-linked to active Cemetech topics. If you are a Cemetech member with a linked United-TI account, you can link United-TI topics here with your current Cemetech topics.

This forum is locked: you cannot post, reply to, or edit topics. 68k Calculator Basic => TI-BASIC
Author Message
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.
Back to top
simonzack


Advanced Newbie


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
Back to top
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.
Back to top
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))
EndFunc


Last edited by Guest on 30 Aug 2010 08:21:46 pm; edited 1 time in total
Back to top
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
Back to top
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
Back to top
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
Back to top
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
Back to top
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.
Back to top
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...
Back to top
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.
Back to top
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
Back to top
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
Back to top
Display posts from previous:   
Register to Join the Conversation
Have your own thoughts to add to this or any other topic? Want to ask a question, offer a suggestion, share your own programs and projects, upload a file to the file archives, get help with calculator and computer programming, or simply chat with like-minded coders and tech and calculator enthusiasts via the site-wide AJAX SAX widget? Registration for a free Cemetech account only takes a minute.

» Go to Registration page
    »
» View previous topic :: View next topic  
Page 1 of 1 » All times are GMT - 5 Hours

 

Advertisement