If you know the equation of the curve, use calculus.

If you dont, consider one of the following:

Eyeball the result.

Adapt the idea in 'Read X and Y value of any point on a chart'
http://www.tushar-mehta.com/excel/ti...lue/index.html

Search the google.com archives of the XL NGs to find code that will
give you how XL computes its smoothened line connecting the points
(Dave Braden's cubic spline code and the bezier curve courtesy
xlrotor.com). Then, use calculus with that equation.

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Regards,

Tushar Mehta
www.tushar-mehta.com
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In article ,
says...
how can i find the coordinatres of the maximum point on a curve plotted in
excel????