I am trying to calculate the first derivative of a curve in excel to
determine the inflection point. I know how to do this in Sigmaplot, but my
students only have access to excel.

Please reply to

The curve in Excel is just a sequence of data points. Fit a curve to the
data (mathematically expression). Take the 2nd derivatiove of the curve and
look for points where the 2nd derivative goes thru zero while switching signs.
--
Gary''s Student


"rgoyan" wrote:

I am trying to calculate the first derivative of a curve in excel to
determine the inflection point. I know how to do this in Sigmaplot, but my
students only have access to excel.

Please reply to

I found a way to do it long hand (so to speak). I was hoping that excel had
a function that would just take the data plot a derivative curve for me from
which I could pick out the maximum. Do you know of any way to do this that
doesn't involve curve fitting? This is for a pH titration curve.

Thanks for your help.

"Gary''s Student" wrote:

The curve in Excel is just a sequence of data points. Fit a curve to the
data (mathematically expression). Take the 2nd derivatiove of the curve and
look for points where the 2nd derivative goes thru zero while switching signs.
--
Gary''s Student


"rgoyan" wrote:

I am trying to calculate the first derivative of a curve in excel to
determine the inflection point. I know how to do this in Sigmaplot, but my
students only have access to excel.

Please reply to

Estimating the first derivative is not diffiuclt. Let's say the x's are in
column A and the y's are in column B. In C2 enter:

=(B3-B1)/(A3-A1) and copy down the column. This is an estimate of dy/dx
at the point [A2,B2]. In a similar fashion you can estimate the second
derivative in column D.
--
Gary's Student


"rgoyan" wrote:

I found a way to do it long hand (so to speak). I was hoping that excel had
a function that would just take the data plot a derivative curve for me from
which I could pick out the maximum. Do you know of any way to do this that
doesn't involve curve fitting? This is for a pH titration curve.

Thanks for your help.

"Gary''s Student" wrote:

The curve in Excel is just a sequence of data points. Fit a curve to the
data (mathematically expression). Take the 2nd derivatiove of the curve and
look for points where the 2nd derivative goes thru zero while switching signs.
--
Gary''s Student


"rgoyan" wrote:

I am trying to calculate the first derivative of a curve in excel to
determine the inflection point. I know how to do this in Sigmaplot, but my
students only have access to excel.

Please reply to