"Bernard Liengme" wrote:
We can find I by rearranging you equation to give
I =((11.4*L^0.5)*(K^0.52)*(S^-0.318)/T)^(1/0.38)
[....]
BTW: Joe has a good idea about using Solver it you want to
avoid to the math to rearrange the equation.

No, I wholeheartedly endorse an algebraic approach. I misread the OP. I
thought we had one equation and 4 unknowns. Looking back, I see that Chris
wrote "L, K & S are constants", so they do not vary. My bad!

(PS: If Chris does choose to use Solver, the set-up is different and much
simpler than I described.)

However....


I get the impression you have a table and you what to find quantity
i by interpolation

That is not how I understood the OP. Chris wrote: ``once "T" is solved for
it is compared with the time value used in the table that "i" was
determined from. If necessary, a new value of "i" is determined and the
equation is solved again. This is repeated until an acceptable tolerance
between "T" and the value used to determine "i" is reached``.

My interpretation is that "a new value of 'i' is determined" by selection
from the table. That is, "i" must be one of the discrete values in the
table. Chris is looking for the discrete value for "i" that results in the
closest value of "T".

I do not have time to give this much thought. But my interpretation is
right, I think one approach is:

1. In parallel with each "i" in the table, compute a corresponding "T" and
ABS(T-i). It might be possible to hide these columns or rows.

2. Use a formula (TBD) to find return the "i" in the table that corresponds
to the smallest ABS(T-i). I believe that's an INDEX(MATCH(MIN)) formula,
off the top of my head.


----- original message -----

"Bernard Liengme" wrote in message
...
Hi Chris,
Excel can be used to solve explicit equation (equations where the unknown
appears on both sides)
But your equation is implicit
We can find I by rearranging you equation to give
I =((11.4*L^0.5)*(K^0.52)*(S^-0.318)/T)^(1/0.38)

But I get the impression you have a table and you what to find quantity i
by interpolation
Happy to have private email from you (this looks a bit off the beaten path
for most readers)
Get my email addy from my web site

BTW: Joe has a good idea about using Solver it you want to avoid to the
math to rearrange the equation.
best wishes
--
Bernard Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme



"Chris" wrote in message
...
I am trying to solve the equation
T=(11.4L^0.5)(K^0.52)(S^-0.318)(i^-0.38),
where "L, K & S" are constants and "i" is determined from a table based
on
time. "T" is time in minutes. To solve the equation fully, once "T" is
solved for it is compared with the time value used in the table that "i"
was
determined from. If necessary, a new value of "i" is determined and the
equation is solved again. This is repeated until an acceptable tolerance
between "T" and the value used to determine "i" is reached. Is there an
easy
way to set this up in excel to run an iterative process with a table?
Any
help would be greatly appreciated.