Re: Equation behind the Function

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Thanks for clearing that up, Mike.

When spread*** programs first came out, I recall running the equations in
the documentation through my HP12c calculator to verify results. (I sure
don't miss those days) Maybe it was 1-2-3's documentation.

The PV function in Excel Help only shows the one equation, though, and the
other related functions refer to the PV page. I suppose that for someone with
the appropriate math skills, solving for any individual component shouldn't
be too difficult.

***********
Regards,
Ron

XL2002, WinXP


"Mike Middleton" wrote:

Ron -

The mathematical equation is in the PV work*** function Help topic.

The equation includes PV, RATE, NPER, and FV, with the explanation that
Excel "solves for one financial argument in terms of the others."

The Help topics for Excel 2003 seem to be essentially the same as the topics
in my copy of the Function Reference paperback for Excel 4.

- Mike

"Ron Coderre" <ronREMOVETHIScoderre@xxxxxxxxxxx> wrote in message
news:6B713710-92D2-48D5-A1F6-0CB48FA0EC64@xxxxxxxxxxxxxxxx
Yes...there are some mathematical equations for some of the functions,
like
the PV function. But, what about the PMT function that the OP mentioned in
the first post? or the FV function? or so many more?

Again, as I recall, the Excel 4 documention displayed the math behind many
more functions.

***********
Regards,
Ron

XL2002, WinXP


"Mike Middleton" wrote:

See Excel's Help for the "PV work*** function" topic.

- Mike

"Ron Coderre" <ronREMOVETHIScoderre@xxxxxxxxxxx> wrote in message
news:6BC7EC5B-F245-4537-A3F2-112CAF4DB363@xxxxxxxxxxxxxxxx
Try eBay

I couldn't find the documentation anywhere else

***********
Regards,
Ron

XL2002, WinXP


"ai18ma" wrote:

Thank you Ron! That is exactly what I wish to see: the "real math"
behind
the
equations and not just how to use them.

How can I get a hold of that "functions book for Excel 4"? I presume
there
no longer are such functions books for newer Excel versions? Once
again,
many
thanks.


"Ron Coderre" wrote:

Have we gotten so far away from "real math" that we forget that
Excel's
functions are not math, but are actually doing the math for us?

The Excel help documentation explains how to use the PMT function,
not
the
mathematics behind that function. Back when Excel 4 came out...in a
box....with 10 disks....and with books...there was a functions book
that
included all of the math used to derive each function's results.

In the case of the PMT function, that documentation went something
like
this:
---------------------

P = (Pv*R) / [1 - (1 + R)^(-n)]

where

Pv = Present Value (beginning value or amount of loan)
APR = Annual Percentage Rate (one year time period)
R = Periodic Interest Rate = APR/ # of interest periods per year
P = Monthly Payment
n = # of interest periods for overall time period (i.e.,
interest
periods per year * number of years)
---------------------

I believe that's what the OP was hoping to find.

I haven't seen that kind of function documentation for Excel in
quite
some
time.
***********
Regards,
Ron

XL2002, WinXP


"Fred Smith" wrote:

Yes, they do. As you've been told, it's in Help. It's actually
pretty
straightforward. What is it about the formula in Help that you
don't
understand?

--
Regards,
Fred


"ai18ma" <ai18ma@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:63C5B1B5-E58E-482F-9E6C-7380191E85F8@xxxxxxxxxxxxxxxx
Many Thanks for the suggestions as well as the offer to help
with
the
specific equation. Nonetheless, it is not just pmt, I would very
much like to
have a better undertanding of the whole issue. Does Microsoft
publish such
information somewhere?

"ai18ma" wrote:

Good Day,

How do I get to see the equation behind Excel Functions? For
instance, the
result of pmt() is not making sense to me, I'd like to see what
this function
is doing and how it is calculating its value. Trial and Error
is
rather
time-consuming and tedious. What is the better way of doing
this?
Thnx for
the help.









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