Re: Help using the INTERPOLATION-function

[Andreas Guelzow <aguelzow pyrshep ca>]

On Tue, 2010-06-08 at 02:02 +0200, Rune Svendsen wrote:
> Hi all!
>
> I'm trying to figure out how to use the INTERPOLATION function, but I'm
> not quite sure how to use it.
> I've been reading up on using functions, but I get an error saying
> "Invalid expression" when I try to use this function.
>
> I do the following:
>
>         1. Enter some data in A1 to A3 (eg. 1, 2, 3) and in B1 to B3
>         (eg. 2, 4, 6)
>         
>         2. In A4 I enter: 4
>         
>         3. I enter the following expression in B4:
>         =INTERPOLATION(A1:A3,B1:B3,A4)
>         
> What I'm trying to do is interpolate for the X-value in A4, using the
> three X-values in A1, A2, A3 and three Y-values in B1, B2, B3, and
> placing the result in B4. What am I doing wrong?

This works fine for me. What is your locale? If you are using a decimal
comma rather than a decimal point (period), then your locale likely uses
the semicolon as an argument separator and it should be:
=INTERPOLATION(A1:A3;B1:B3;A4)

If you use insert->formula to create teh expression then the correct
argument separator will be used automatically.

Andreas