HP -22S Owner's Manual Page 160

Scientific calculator.

Keys:
Display:
Description:
o
'sTol X
Calculates the positive
10.'
SOLVE I
X=2.0000
root using guesses 0
and 10 .
• , LAST ' . ' SHOW I
0.00000000000
I(x)
=
o.
o
'sTOI X
Calculates the negative
10
ElJ.'
SOLVE I
X=-3.0000
root using guesses 0
and -10 .
• , LAST
I.'
SHOW I
0.00000000000
I(x)
=
o.
(x)
-5
5
r-~---4--~r---r---+---~--~--~---r---+--~~x
(x)
=
x
2
+
X -
6
Certain cases require special consideration:
• If the function's graph has a discontinuity that crosses the x-axis,
, SOLVE I
returns a value adjacent to the discontinuity (see figure B-
3a). In this case,
I(x)
may be relatively large .
• Values of f(x) may be approaching infinity at the location where the
graph changes sign (see figure B-3b). This situation is called a
pole.
Since'
SOLVE I
determines that there is a sign change between two
neighboring values of x, it returns the possible root. However, the
value in .,
LAST I
will be relatively large. If the pole occurs at a
value of
x
that is exactly represented with 12 digits,1
SOLVE I
may try
that value and halt with an error message.
160
B: More About Solving Equations  