HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 363

Approximate vs. Exact mode, x + x², x² + x +1, Cmplx, R= STEP

Page 363 highlights

Below the title bar you can see the first section of a series of alternatives which let you manipulate the configuration. Most alternatives are toggles having only two values. For example, choosing Complex and pressing ENTER will cause the menu to momentarily disappear and then re-display with the new setting of Real. Pressing ENTER again will revert back to Complex. It is important to realize that the entry shown in the menu is the one that is NOT in use! For example, if it shows Complex then you are in Real mode and vice versa. Using the menu you can choose: Quit config Complex Approx Direct 1 + x + x² Sloppy Num. factor Cmplx vars English Default cfg (when you're finished making changes) (or Real) (or Exact) (or Step by Step see following page) (or x² + x +1 ; governs how polynomials will display) (or Rigorous, if you want to work in absolute values) (or Symb factor) (or Real vars if you want all symbolic variables to be assumed real) (or Français if you want the help screens to be in French) (which is R= STEP ↓ X 13 ||). Pressing takes you out of the CFG menu (as does choosing QUIT from the menu and confirming it with ) but does not discard any changes you have made. The only difference between the two configuration menus shown right is that the lower one is harder to use and contains one option not available on the upper one - the ability to select French as the language in which the help screens are displayed. The name of the current variable, as well as the value of the variable MODULO, can be changed by means of the SHIFT MODES view, or by using the VARS key. Many of the configurations addressed in the CFG menu are also referenced in these views. Press ON to exit the VARS configuration view. The information supplied in the manual on the various configuration states is quoted below for reference together with comments and suggestions. Approximate vs. Exact mode When the approximate mode is selected, symbolic operations (for example, definite integrals, square roots, etc.), will be calculated numerically. When this mode is unselected, exact mode is active, hence symbolic operations will be calculated as algebraic expressions, whenever possible. [Default: unselected.] Comment: Generally you will want to stay in Exact mode because this gives answers as surds, fractions of pi and so on. If you want a decimal result, simply highlight the expression you want converted and press NUM. Press SHIFT NUM to convert in the other direction. SHIFT NUM is equivalent to calling the XQ function. 363

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Below the title bar you can see the first section of a series of alternatives which let you manipulate the
configuration. Most alternatives are toggles having only two values.
For example, choosing
Complex
and
pressing
ENTER
will cause the menu to momentarily disappear and then re-display with the new setting of
Real
. Pressing
ENTER
again will revert back to
Complex
. It is important to realize that the entry shown in
the menu is the one that is NOT in use!
For example, if it shows
Complex
then you are in
Real
mode and
vice versa.
Using the menu you can choose:
Quit config
(when you’re finished making changes)
Complex
(or
Real
)
Approx
(or
Exact
)
Direct
(or
Step by Step
see following page)
1 + x + x²
(or
x² + x +1
; governs how polynomials will display)
Sloppy
(or
Rigorous
, if you want to work in absolute values)
Num. factor
(or
Symb factor
)
Cmplx
vars
(or
Real
vars if you want all symbolic variables to be assumed real)
English
(or
Français
if you want the help screens to be in French)
Default cfg
(which is
R= STEP
X 13 ||
).
Pressing
takes you out of the
CFG
menu (as does choosing
QUIT
from the menu and confirming it with
) but does not discard any
changes you have made.
The only difference between the two configuration menus shown right is
that the lower one is harder to use and contains one option not available
on the upper one – the ability to select French as the language in which
the help screens are displayed.
The name of the current variable, as well as the value of the variable
MODULO
, can be changed by means of the
SHIFT MODES
view, or
by using the
VARS
key.
Many of the configurations addressed in the
CFG
menu are also referenced in these views.
Press
ON
to exit the
VARS
configuration view.
The information supplied in the manual on the various configuration
states is quoted below for reference together with comments and suggestions.
Approximate vs. Exact mode
When the approximate mode is selected, symbolic operations (for example, definite integrals, square
roots, etc.), will be calculated numerically. When this mode is unselected, exact mode is active, hence
symbolic operations will be calculated as algebraic expressions, whenever possible. [Default:
unselected.]
Comment:
Generally you will want to stay in Exact mode because this gives answers as surds, fractions of
pi and so on.
If you want a decimal result, simply highlight the expression you want converted
and press
NUM
. Press
SHIFT NUM
to convert in the other direction.
SHIFT NUM
is
equivalent to calling the
XQ
function.
363