HP 48gII - Manual (Page 387)

Page 12-6
• If you move the cursor towards the right-hand side of the curve, by
pressing the right-arrow key ( ™), and press @ROOT, the result now is
ROOT: 1.6635... The calculator indicated, before showing the root,
that it was found through
SIGN REVERSAL. Press L to recover the
menu.
• Pressing @ISECT will give you the intersection of the curve with the x-
axis, which is essentially the root. Place the cursor exactly at the root
and press
@ISECT. You will get the same message as before, namely
SIGN REVERSAL, before getting the result I-SECT: 1.6635…. The
@ISECT function is intended to determine the intersection of any two
curves closest to the location of the cursor. In this case, where only
one curve, namely, Y1(X), is involved, the intersection sought is that of
f(x) with the x-axis, however, you must place the cursor right at the
root to produce the same result. Press
L to recover the menu.
• Place the cursor on the curve at any point and press @SLOPE to get the
value of the slope at that point. For example, at the negative root,
SLOPE: 0.16670…. Press
L to recover the menu.
• To determine the highest point in the curve, place the cursor near the
vertex and press @EXTR The result is EXTRM: 0.. Press L to recover
the menu.
• Other buttons available in the first menu are @AREA to calculate the
area under the curve, and @SHADE to shade an area under the curve.
Press L to see more options. The second menu includes one button
called @VIEW that flashes for a few seconds the equation plotted. Press
@VIEW. Alternatively, you can press the button @NEXQ (NEXt eQuation) to
see the name of the function Y1(x). Press
L to recover the menu.
• The button @@F(X)@@ gives the value of f(x) corresponding to the cursor
position. Place the cursor anywhere in the curve and press @@F(X)@@. The
value will be shown in the lower left corner of the display. Press L
to recover the menu.
• Place the cursor in any given point of the trajectory and press TANL
to obtain the equation of the tangent line to the curve at that point.
The equation will be displayed on the lower left corner of the display.
Press
L to recover the menu.
• If you press @@F ' @@ the calculator will plot the derivative function, f'(x)
= df/dx, as well as the original function, f(x). Notice that the two