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)