I'm not aware of such a feature in the various chart menus, but you can
calculate the area directly from the data used for the chart curve.
You don't even need to make a chart, except as an aid in visualizing
the curve.
Let's suppose you have the x values in cells A1:A100, and y values in
B1:B100.
Then, in column C, do the following:
1. Put this formula in cell C1 (area contribution from the first data
point):
=B1*(A2-A1)/2
2. Put this formula in cell C2 (area contrib. from 2nd data point):
= B2*(A3-A1)/2
3. Copy the formula in cell C2 to cells C3 through C99, i.e. up to the
2nd-to-last data point.
4. Put this formula in cell C100, or wherever the last data point's row
is:
=B100*(A100-A99)/2
5. The area is the sum of all values in column C. So in cell D1, type
= sum(C1:C100)
This will work even if the x values are not evenly incremented. There
are more accurate ways to do this, but this method is the simplest I
know of.
Mark
