HP (Hewlett-Packard) F2215AA#ABA ユーザーズマニュアル

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D-13
Solve for X using initial guesses of 10
–8
 and –10
–8
.
Round–Off Error
The limited (12–digit) precision of the calculator can cause errors due to rounding 
off, which adversely affect the iterative solutions of SOLVE and integration. For 
example,
has no roots because f(x) is always greater than zero. However, given initial guesses 
of 1 and 2, SOLVE returns the answer 1.0000 due to round–off error.
Round–off error can also cause SOLVE to fail to find a root. The equation
has a root at 
. However, no 12–digit number exactly equals 
, so the 
calculator can never make the function equal to zero. Furthermore, the function 
never changes sign SOLVE returns the message   . 
Keys:
(In RPN mode)
Display:
Description:

 
X
 
 

 

_
Enters guesses.
J


Selects program "J" as the function.
X


Solves for X; displays the result.
0
 
 
10
 -
 
]
10
 
 
1)
 
 
x
 
[(
30
2
15
=
+
+
0
 
 
7
-
x
2
=
7
7