First Derivative

Originally Posted by shg

I'm missing the objective; why not reduce the data first, then take the derivative of what's left?

You could reduce the data by decimation, or by taking a centered moving average of every 3, 5, whatever, points.

Yes I have already done that. The data I have is after I did 3 point moving average. I am not performing 4 or 5 point moving average because my analysis involves looking at the exact position of slope change in the data and after trials on various data, 3 point averaging works best. But the amount of data is still large enough (and hence more scatter) that I am not able to recognize the exact position of the slope change when I plot the derivative as a function of the variable. So if I do a derivative by skipping a point and then plot the derivative as the function of the variable, I reduce the data further and I have my bosses quoting that it smoothens the plot as well. And hence this painful process.

Thanks for your help. Let me know

Originally Posted by shg

In D5, =(B6-B4)/(C6-C4)

Select D5:D7 (i.e., D5 and the two empty cells below) and drag down the fill handle.

Perfect! Thank you.... It was way easier and I expected it to be..