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 (E-Mail Removed)