PASCO Xplorer-GLX Users’ Guide - Manual (Page 48)

42 C a l c u l a t o r
• Press the up arrow key to put the cursor back on the above expression and
modify it to read:
9 * (9 + 3)
When you type something into the middle of an existing expression, the new
characters are inserted without overwriting anything; press
to delete the
characters that you don’t want.
Note that the correct result does not appear until you have moved the cursor
to a different line by pressing
or , or the up or down arrow key.
Algebraic Calculations
Algebraic calculations involve symbols (letters or words) standing for constants.
When you enter an algebraic expression, the GLX fills in the result if it knows
the value of every symbol used in the expression. If it does not know the value of
a symbol, it will prompt you to enter it.
If you are entering an equation to be graphed, leave one symbol undefined.
See “Graphing Equations” on page 44 for more information.
Try these examples:
• Type:
a + 3
For the a symbol, press twice to open the second Functions menu. Use
the arrow keys to highlight
a
, then press .
For more information on the Functions menus, see page 48.
The Calculator does not know the value of a, so it prompts you with:
a =
Type:
5
The Calculator fills in the result of the original expression.
• Try entering a new value for a on the next line: 4
a = 6
Note that the original expression still reads
a + 3 = 8
This expression has just been
modified, but the user has not yet
pressed or so it appears to
show an incorrect result.
=
Õ
=
F1
press twice F1
Second Functions menu
The Calculator fills in the result of a+3
when the value of a is entered.
4 For the a symbol, press twice
and select it from the second Functions
menu.
F2