HP 48G Series

Lesson 26: Finding Roots Graphically
In Lesson 17, you found all of the roots of a polynomial using the
SOLVE application. This lesson shows you how to use the special
analytic tools in the PICTURE environment to find the roots of a
function visually as well as search for other information about a
function.
Example: Plot the function, X°® + X* — 5X3 — 2X2 + X — 4, and
find its real roots.
Step 1: Begin the PLOT application and reset the plot display
options.
@ 0 @E FO ED
RESET
(VM)
0K
TVR
EQ: PEE TT PRN)
INDEP: H-VIEW: -5.5 6.5
_AUTOSCALE Y-VIEW: -3,1 2.2
ENTER FUNCTION(S) TO PLOT
RESET] CHLC [TYPES] [CAMO] OK
EB: Function :
[IE ON]
Step 2: Enter the function.
@(EauATon) PLOT
E
EQ: " B f) rt or n in
INDEP: ¥ H-VIEW: —56.5 6.5
_HAUTOSCALE Y-VIEW:-3,1 3.2
EMTER FUNCTION(S) TO PLOT
[E0T [cHOD:] OPT: [ERAZE[ DR]
Step 3: Erase the “blackboard” (the PICTURE display) and draw
the function.
[200M ci. [TRACE] FCNEIT JEANIL
Plotting Equations and Analyzing Graphs 6-13