Interpolation problem, need hepl

Hello everyone, I need to do interpolation of the following table
1 1,oo2 +0,002 ±0,0010
2 2,003 +0,003 ±0,0025
3 3,003 +0,003 ±0,0025
4 4,004 +0,004 ±0,0030
5 5,002 +0,002 ±0,0010
6 6,003 +0,003 ±0,0025
7 7,003 +0,003 ±0,0025
8 8,004 +0,004 ±0,0030
9 9,004 +0,004 ±0,0030
10 10,003 +0,003 ±0,0025

So if you enter a value of 1.3 to get the results of the remaining lines,
Thank you all in advance

What result(3) do you expect for 1.3? Can I assume you are wanting to linearly interpolate?

Linear interpolation is not difficult if you are willing to spread it out over several cells. When I do it, it will look something like:

cell 1) =MATCH(new_x,known_x's) This returns the interval that contains new_x (1.3 in your example)
cells 2 and 3) =INDEX(known_x's,cell1) and cell1+1 These two return the known_x's for the interval found in cell 1.
cells 3 and 4) =INDEX(known_y's,cell1) and cell1 +1 These two return the known_y's for the interval found in cell 1.
cell 5) =TREND(cells3:4,cells2:3,new_x) This does the actual linear interpolation based on the interval containing new_x.

This post is in the programming section, suggesting you might want a VBA solution. Putting the above into VBA is not difficult. The MATCH function is available to VBA (see VBA help for using worksheet functions in VBA). Once you've found the interval inside the range that contains new_x, the linear interpolation is easy. (Y3-Y1)/(X3-X1)=(Y2-Y1)/(X2-X1) solved for the appropriate variable.

If possible I would like visual basic solution,
and I need a linear interpolation of the lines,
so that bringing in random value of 1 to 10 (eg 1.3, 1.7, 5.9, 8.7, etc.).

Thanks a lot

So, do you need someone to write the code for you? As I said, this isn't a difficult function to write. Here's a skeleton you can work with to build a UDF that you can call like a regular function from the worksheet:

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That was quickly and sloppily done, so check my syntax and my algebra to make sure it is right. You may also want to add some "error handling" to deal with cases where new x is outside of the range of known_x.

Can you explain me how to determine the numbers between is written number, I imagined something like this:

Sub Interpolacija()

Dim x0 As Double, y0 As Double, z0 As Double, x1 As Double, y1 As Double, z1 As Double
Dim differenceInX As Double
Dim differenceInY As Double
Dim Unos As Double
Dim Row As Integer

Unos = InputBox("Unesite velicinu")

For Row = 2 To 12
If ThisWorkbook.Sheets("Sheet1").Cells(Row, 1) = Unos Then
MsgBox "uneta velicina vec postoji"
Else
If ThisWorkbook.Sheets("Sheet1").Cells(Row, 1) > Unos Then

x0 = ThisWorkbook.Sheets("Sheet1").Cells(Row, 1)
x1 = ThisWorkbook.Sheets("Sheet1").Cells(Row - 2, 1)

y0 = ThisWorkbook.Sheets("Sheet1").Cells(Row, 1)
y1 = ThisWorkbook.Sheets("Sheet1").Cells(Row - 2, 1)

z0 = ThisWorkbook.Sheets("Sheet1").Cells(Row, 1)
z1 = ThisWorkbook.Sheets("Sheet1").Cells(Row - 2, 1)
Next Row
End If
End If
End Sub

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Can you explain me how to determine the numbers between is written number, I imagined something like this:

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The code you have looks like it should do fine locating the interval containing unos. You appear to have made the mistake of having z0, y0, and x0 all be the same value, so you need to change those statements to extract the correct values from the table. maybe y0 should be y0=thisworkbook.sheets("sheet1").cells(row,2).

Having located the interval containing unos (which is the most difficult part of linear interpolation in my opinion) it should be as simple as putting the corresponding values into the linear interpolation formula given above. Am I misunderstanding your question?

Everything is fine, I understand what you say, the only problem is that my code will not want to execute, there is an error and I can not figure out where

Did it give you an error message, or does it just refuse to run? Did it give you a "next without for" type error or indicate an error in the block if's? Your code gave me a next without for message, which suggests that you need to move your end if statements so they are inside the loop.

refuses to work... I didn't a long time deal with Visual Basic, so now all is a problem for me ...

I'm not sure what to say. when I correct the next without for error, the code seems to run just fine for me.

Perhaps your installation of VBA doesn't like using Row as a variable name, since Row is also a property of the range collection, causing the compiler to crash over the name confusion.