area under a curve in Excel
 

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

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?

See Bernard Liengme's
http://www.stfx.ca/people/bliengme/E...UnderCurve.htm and
http://www.stfx.ca/people/bliengme/E...olygonArea.htm

--
Regards,

Tushar Mehta
www.tushar-mehta.com
Excel, PowerPoint, and VBA add-ins, tutorials
Custom MS Office productivity solutions

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