Scott -

the original equation is the first part of what Henry wrote
  pimf=: (1.10 * 50 -~ ])     NB. Plus 10% Interest, Minus $50 Fee

Applying this over 3 years using the power adverb:
  pimf3=: pimf^:3              NB. Apply to self recursively 3 times

  pimf3 1000                    NB. starting with $1000
1148.95

Use "power" with parameter of negative one to derive the inverse function:
  pimf3^:_1                      NB. Inverse of "pimf3"
+-----+--+--+
|pimf3|^:|_1|
+-----+--+--+
  pimf3^:_1 (1000)       NB. Inverse of "pimf3" applied to $1000
888.09166
  pimf3 888.09166      NB. Check answer
1000

Devon

On 5/8/06, Scott Russell <[EMAIL PROTECTED]> wrote:

Thanks Henry.

Can you give me the original equation and then how do you make an inverse
of the equation ?

Scott

  ----- Original Message -----
  From: Henry Rich<mailto:[EMAIL PROTECTED]>
  To: 'Programming forum'<mailto:[email protected]>
  Sent: Monday, May 08, 2006 2:59 PM
  Subject: RE: [Jprogramming] J question


  I would never have thought of doing it this way, but you can
  solve it in J just as you would in Excel.  Defines the function,
  and use the inverse to ask what value would give you 1000:

    (1.10 * 50 -~ ])^:3 ^:_1 (1000)
  888.092

  Henry Rich

  > -----Original Message-----
  > From: [EMAIL PROTECTED]<mailto:
[EMAIL PROTECTED]


...
--
Devon McCormick
^me^ at acm.
org is my
preferred e-mail
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