HP Prime Graphing Calculator - Manual (Page 144)

140 Geometry
tangent changes in Plot view, the value of the slope is
automatically updated in Numeric view.
26.With the new calculation highlighted in Numeric view,
tap .
Selecting a calculation in Numeric view means that it will
also be displayed in Plot view.
27. Press P to return to
Plot view.
Notice the calculation
that you have just
created in Numeric view
is displayed at the top
left of the screen.
Let’s now add two more
calculations to Numeric view and have them displayed
in Plot view.
28.Press M to return to Numeric view.
29. Tap , enter GB, and tap .
Entering just the name of a point will show its
coordinates.
30.Tap , enter GC, and tap .
Entering just the name of a line will show its equation.
31. Make sure both of these new equations are selected (by
choosing each one and pressing ).
32. Press P to return to
Plot view.
Notice that your new
calculations are
displayed.
33.Press E and
choose point GB.
34.Use the cursor keys to move point B along the graph.
Note that with each move, the results of the calculations
shown at the top left of the screen change.
Trace the
derivative
Point D is the point whose ordinate value matches the
derivative of the curve at point B. It is easier to see how the