HP 40gs User Manual page 68

Analyse graph
with FCN
functions
To find a root of the
quadratic function
To find the
intersection of the
two functions
3-4
9. Display the Plot view menu.
From the Plot view menu, you can use the functions
on the FCN menu to find roots, intersections, slopes,
and areas for a function defined in the Function aplet
(and any Function-based aplets). The FCN functions
act on the currently selected graph. See "FCN
functions" on page 3-10 for further information.
10.Move the cursor to the graph of the quadratic
equation by pressing the
the cursor so that it is near
or key.
Select Root
The root value is
displayed at the
bottom of the screen.
Note: If there is more
than one root (as in our
example), the
coordinates of the root closest to the current cursor
position are displayed.
11.Find the intersection of the two functions.
or key. Then move
x = 1 –
by pressing the
Function aplet