You can use the FORECAST() function to interpolate as well as extrapolate.

See Excel Help
--
Gary's Student


"Steve" wrote:

Hi

This is probably a simple task and it is my own lack of experience in
Excel -- I would like to derive a y value for an arbitrary x value from a
array of known x's and known y's for some unknown function y = f(x) a la:

known x, y
0.123, 4.567
0.257, 10.4567
0.4321, 20.3241
0.703, 10.345
0.804, 2.345

say I want to derive a y value for x=0.5 from this data set using a linear
or higher order fit -- is there an appropriate worksheet function for this
or do I have to resort to programming?

Many thanks in advance.
Steve

"Gary''s Student" wrote in message
...
You can use the FORECAST() function to interpolate as well as extrapolate.

FORECAST seems to do only linear line fit -- my data is an arbitrary fixed
waveform for which Im trying to fill in missing points -- is there some
trick I need to apply to make forecast work at a higher order?


See Excel Help
--
Gary's Student


"Steve" wrote:

Hi

This is probably a simple task and it is my own lack of experience in
Excel -- I would like to derive a y value for an arbitrary x value from a
array of known x's and known y's for some unknown function y = f(x) a la:

known x, y
0.123, 4.567
0.257, 10.4567
0.4321, 20.3241
0.703, 10.345
0.804, 2.345

say I want to derive a y value for x=0.5 from this data set using a
linear
or higher order fit -- is there an appropriate worksheet function for
this
or do I have to resort to programming?

Many thanks in advance.
Steve