in-between chart values

[Guest]

excel makes a chart of a given x and y range. now i like
excel to display an in-between x value correctly on the
existing chart (so excel has to calculate the y value).
is this possible?

 

[dvt]

excel makes a chart of a given x and y range. now i like
excel to display an in-between x value correctly on the
existing chart (so excel has to calculate the y value).
is this possible?

I think you need to use the TREND function on your worksheet, then plot
the computed data on your chart. You might also use the LINEST function
in some instances, but try Excel's help under the TREND function to get
started.