Graphing the 1st Derivative on excel?

[higherme]

I have a titration curve (pH vs NaOH added) and i want to determine the endpoint of this graph
i want to use excel to make a graph of it's derivative (dy/dx) but i don't know how?

does anyone know how?
is there an option i can choose when making the graph?

 

[chemisttree]

You can calculate dy/dx (actually delta pH/delta volume) and graph the result. Pretty straightforward that way.