Ionman,

As an example, assume you set up an XY chart with these data points. The
title "X" is in cell A1 and the entire range covers A1:C11. The points in
column X are hardcoded:

X Y Areas
0 0.000 12.856
40 0.643 32.552
80 0.985 37.017
120 0.866 24.161
160 0.342 6.840
200 -0.342 24.161
240 -0.866 37.017
280 -0.985 32.552
320 -0.643 12.856
360 0.000

The formula in cell B2 is:

=SIN(RADIANS(A2))

Copy this formula down column C until you hit cell B11.

To calculate the area, add this formula to cell C2:

=IF(B2*B3=0,ABS(((B2+B3)/2)*(A3-A2)),ABS(((B2^2+B3^2)/(B2-B3)/2)*(A3-A2)))

Copy the formula down the range of cell C2 to cell C10. Total the results
in range C2:C10 to calculate the total area.

This formula is not truly accurate as shown above. Generally, the more data
points that you add the better the more accurate the results.

----
Regards,
John Mansfield
http://www.pdbook.com



"ionman" wrote:

how do I calculate the area under a graph that I have plotted using excel?