HP 33s hp 33s_user's manual_English_E_HDPM20PIE56.pdf - Page 337

Round–Off Error

Page 337 highlights

Checksum and length: B956 75 You can subsequently delete line J0003 to save memory. Solve for X using initial guesses of 10-8 and -10-8. Keys: (In RPN mode) Display: Description: a8^IX 1^a8^ |W J  X %/ .)  Enters guesses. Selects program "J" as the function. Solves for X; displays the result. 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, [( x + 1) + 1015]2 - 1030 = 0 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 x2 - 7 = 0 has a root at 7 . However, no 12-digit number exactly equals 7 , so the calculator can never make the function equal to zero. Furthermore, the function never changes sign SOLVE returns the message However, the final estimate of x (press b to see it) is the best possible 12-digit approximation of the root when the routine quits. More about Solving D-13

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More about Solving
D–13
Checksum and length: B956
75
You can subsequently delete line J0003 to save memory.
Solve for X using initial guesses of 10
–8
and –10
–8
.
Keys:
(In RPN mode)
Display:
Description:
8
X
1
8
_
Enters guesses.
J
Selects program "J" as the
function.
X
Solves for
X
; displays the result.
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,
0
10
-
]
10
1)
x
[(
30
2
15
=
+
+
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
0
7
-
x
2
=
has a root at
7
. However, no 12–digit number
exactly
equals
7
, so the
calculator can never make the function equal to zero. Furthermore, the function
never changes sign SOLVE returns the message
. However, the final
estimate of
x
(press
to see it) is the best possible 12–digit approximation of
the root when the routine quits.