EC-4044 (650-0808) Operation Faxback Doc. # 3482
Resetting the calculator
Using reset can select all default settings and clear
everything. Because there are other ways to clear that
affect only specific items, you should reserve the
reset function for appropriate situations. You might
choose to reset when you first purchase the calculator,
or when required to in a classroom situation.
Alternatives to Before you use reset, consider the other methods for
Resetting clearing described on the next page. For example you
can clear an individual formula without resetting.
Reset Procedure When you press 3rd [RESET], the calculator exits from
any sequenced entries or results and clears any entry
in progress. Then:
1. The display shows Defaults YN?
-> To leave the settings unaffected, respond N.
-> To reset the six settings, respond Y.
Angle unit resets to degrees.
Default number base resets to decimal.
Complex number form resets to rectangular.
Digits of precision resets to 10 digits.
Notation resets to standard.
Fixed decimal format resets to floating.
2. The display shows Clr Mem YN?
-> To leave memory intact and end the reset
sequence, respond N.
-> To choose to clear the memory, respond Y.
3. The display shows Confirm YN? This prompt gives
you the chance to reconsider because memory may
contain formulas or other data that would be
difficult to restore.
-> To leave memory intact and end the reset
sequence, respond N.
-> To clear all variables, formulas, and the
statistics data set, respond Y. The message
Cleared is shown.
Clearing
You can clear individual items or certain groups of
items with the key sequences listed below.
Methods of The following table helps you use the clearing
Clearing features.
Item to Clear Method
Entry line Press CLEAR.
An Incomplete fix or Rcl, but not Press CLEAR.
other items of the current entry
A value asked for in a prompt, but Press CLEAR.
not the prompt
Sequence of results Press any key
other than <-, ->,
= ENTER, 2nd
[NEXT], 2nd [BACK],
or STO.
Statistics data set Press 2nd [CS] Y.
An individual formula or variable Use 2nd [VAR] or
2nd [FMLA] to
specify the name
and press 3rd [CFV]
Y.
All variables Press 3rd [CVs] Y.
Computational Accuracy
The calculator achieves its accuracy by having more
digits internally than are shown in the display. These
extra internal digits guard against visible
inaccuracies by keeping roundoff error past the 10th
digit, and are called guard digits. You can select two
ways for the guard digits to be used.
Digits of The two choices for the digits of precision are:
Precision
-> 10 -digit - Results appear with up to 10 digits.
Settings For calculations executed together in the same
entry, 10 digit- precision keeps the guard digits
until the answer appears, showing the same result
as 13-digit precision. However, slight differences
may become visible in successive calculations. The
advantage of 10 digit precision is that most
numbers are more compact in a subsequent
calculation.
-> 13-digit - Results appear with up to 10 digits,
internally the guard digits remain to preserve
accuracy. A number, when used in a subsequent
calculation, occupies up to 13 digits in the entry
line for the 13-digit setting, compared to a
maximum of 210 digits in the 10-digit setting.
To switch between 10-digit and 13-digit and 13-digit
precision, press 2nd [13>].
Rounding a Result If a calculation produces a result that is more than
10 digits, the calculator uses the guard digits to
determine how to display the result.
-> If the first digit past the visible display is 5 or
greater, the calculator automatically rounds the
result to the next larger value in the last
displayed digit.
-> If the first digit past the visible display is 4 or
less, the guard digits do not affect the displayed
result.
If 10-digit precision is selected, the internal value
is replaced with the 10-digit rounded value after all
calculations in the entry line are completed. If
13-digit precision is selected, the unrounded result
remains for subsequent calculations.
The Round The round function (rnd) rounds the internal value to
Function 10 digits. If you use Rnd with a complex number, both
parts are rounded. The syntax for rounding a number
is:
rnd number
1. Begin with the rnd function (3rd [RND]).
2. Follow it with the number or expression that is
being rounded.
To execute an entry, press =ENTER.
Comparison of Consider the problem X 2.4207 x 2.165. The true
Internal and result is 10.00000005555.
Displayed
Results The calculator shows 10.00000006 when set to floating
decimal notation and has the following internal
results.
Internal result for 13-digit setting 10.00000005555
Internal result for 10-digit setting 10.00000006000
Internal result of
rnd(1.9081 X 2.4207 X 2.165 10.00000006000
If the calculation is entered with rounding, the
internal result is the same for either 10-digit or
13-digit precision.
(br/all-12/12/94)