How to Generate a Function for Polynomial Interpolation in Excel

[brad sue]

Hi ,
I have to generate a function on excel that does the following

the problem is about polynomial interpolation.

I have for example a column of values:
-100
0
100
200
300
400

First , I need to find the value in the table that is 2 point above the input value.
For example , if my input value is 118 the first value is 0.

Second, my real problem is how to select the next four values ( and use them else where).

For the same example, if we enter 118, the corresponding colum must be:
0
100
200
300

I don't know how to go from a cell to another cell using a formula.
I hope that you can understand me.

thank you for your help

 

[Andre]

I'm a bit autodidactic in Excel and I'd love to see too somebody to show how coordinates of cells could be generated by a numerical expression. As the problem is now, I figure you need a lot of (nested) copy pasted fuctions like IF(condition; output if true; output if false).

Success.

 

[Andre]

Got the spreadsheet ready. Not a big deal. I used "AND" functions to determine in between-which value the input is. Then IF functions to get the series corresponding with it. And MAX functions to get that particular series into the output cells. So, how would you do it?

 

[brad sue]

Got the spreadsheet ready. Not a big deal. I used "AND" functions to determine in between-which value the input is. Then IF functions to get the series corresponding with it. And MAX functions to get that particular series into the output cells. So, how would you do it?

thanks I ll be back soon