The turning point tool finds accurate turning points of y=f(x) and x=f(y) functions and inequalities.
Select the turning point tool by clicking the button on the graph tools tool bar, or by selecting the 'Turning point' command from the 'Tools' menu. The turning point tool cursor: is then displayed on the graph view, and the turning point tool dialog box is displayed. (See below:)
Plotting the turning points:
All points found by the turning point tool are stored in memory. Click the 'Plot' button to plot all of the stored points and clear the memory.
Click the 'Clear' button to erase the point memory.
Note: The turning point tool is capable of very high accuracy, even if you don't click exactly on a turning point. It uses the point you click on as an initial estimate only.