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How do I find points on a curve between known points?
I have a Logarithmic curve with points that do not match my Y-axis values.
How can I find the points that intercept my Y-axis major grid lines? I can extrapolate the curve easily, but I cannot figure how to find other points on the curve. |
#2
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How do I find points on a curve between known points?
First get the equation of the trendline into cells but not by manually
copying it. See http://www.tushar-mehta.com/excel/ti...efficients.htm http://people.stfx.ca/bliengme/ExcelTips/Polynomial.htm Then do some algebra. What is the equation of the trendline? Suppose it is y=aLn(x)+b. Do you want the value of y when x = 2? y= a*Ln(2)+b - use a spreadsheet! Or do you want the value of x when y = 5? ln(x) = 5/a -b. Let this be c So Ln(x) = c , then x = EXP(c) best wishes -- Bernard V Liengme www.stfx.ca/people/bliengme remove caps from email "Cybertori" wrote in message ... I have a Logarithmic curve with points that do not match my Y-axis values. How can I find the points that intercept my Y-axis major grid lines? I can extrapolate the curve easily, but I cannot figure how to find other points on the curve. |
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