Iterative Process

[nasos]

Dear all,
I would like some advice on whether is possible to solve in Excel the following problem and maybe some help with the solution.
I have the following equation: Y = I * B(Y) (1)
The magnitude of B depends on Y and I have a table of values of B vs Y
Y...............B
110.00.......1293.75
125.00.......1162.50
140.00.......1050.00
175.00.......993.75
230.00.......956.25
225.00.......918.75
400.00.......712.50
500.00.......637.50
700.00.......581.25
etc
Also I have a table of I vs t values:
t...........I
10.........1
50.........0.9
100.......075
200.......0.6
500.......0.2
1000.....0.08
2000 ....0.06
5000.....0.05
etc

I need to plot Y vs t that satisfies equation 1.
I have previously solved this problem by dividing the values of Y/B of the first table to get the corresponding I' values. Then used interpolation between the I values of second table to get the corresponding t values and finally plotted t against Y.

I am looking for an iterative solution with Excel that i can adjust to different data. Any thoughts would be strongly appreciated.
Thanks,
NAsh

 

[nasos]

Hi,
I havent received any answers so far so I would just like to ask whether it is because the problem is not clear or too complicated ( or too simple?) for excel.
I would be more than happy to discuss/clarify any point necessary in exchange of any ideas of feedback possible.
Thanks,
Nash

 

[baitmaster]

I think your problem is that you are presenting in math terms, rather than in Excel terms. It's been a long time since I studied maths, and I'm struggling to work out exactly what you are trying to do

As a simple answer, Excel can help you with this. From this board, you will almost certainly receive formulas and or macros that will answer your question (both can usually be used for iterative processes). For me, the exact nature of the problem is unclear

Can you please clarify the exact steps /algorithm you are trying to perform, and the problem you are encountering

 

[nasos]

Re: Iterative Process/Interpolation

Thanks for your reply. I have been trying to reproduce a curve from a standard that i know that it was done in EXCEL but Im not aware of the process. At this point I believe that it might be an issue of the interpolation method used. Im trying to interpolate between X and Y for the Xnew values

<table style="border-collapse: collapse; width: 299pt;" border="0" cellpadding="0" cellspacing="0" width="399"><col style="width: 141pt;" width="188"> <col style="width: 110pt;" width="147"> <col style="width: 48pt;" width="64"> <tbody><tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt; width: 141pt;" width="188" height="17">Y</td> <td class="xl65" style="width: 110pt;" width="147">X</td> <td style="width: 48pt;" width="64"> Xnew</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">25</td> <td class="xl65">0.01025641</td> <td align="right">0.9</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">50</td> <td class="xl65">0.026666667</td> <td align="right">0.75</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">75</td> <td class="xl65">0.05</td> <td align="right">0.6</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">100</td> <td class="xl65">0.077294686</td> <td align="right">0.2</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">125</td> <td class="xl65">0.107526882</td> <td align="right">0.08</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">150</td> <td class="xl65">0.142857143</td> <td align="right">0.06</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">175</td> <td class="xl65">0.176100629</td> <td align="right">0.051</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">200</td> <td class="xl65">0.209150327</td> <td align="right">0.05</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">225</td> <td class="xl65">0.244897959</td> <td>
</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">400</td> <td class="xl65">0.561403509</td> <td>
</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">500</td> <td class="xl65">0.784313725</td> <td>
</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">700</td> <td class="xl65">1.204301075</td> <td>
</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl65" style="height: 12.75pt;" height="17">1000</td> <td class="xl65">1.720430108</td> <td>
</td> </tr> </tbody></table>
Ive used the TREND function but the results are not quite there. Is there a better method that I can use in excel for this set of data? (or any other method).
Thanks for your time