You can use the Boolean variables true and false in
GeoGebra. Just type, for example,
a = true or b = false into the Input Bar and
press the Enter-key.
Free Boolean variables can be
displayed as check boxes in the Graphics View (see tool
Check Box to Show/Hide objects). By using
the arrow keys of your keyboard you may also change Boolean variables in the Algebra View
(see section Manual
Animation).
Note: You may also use Boolean variables like numbers (value 0 or 1). This allows you to use a checkbox as the dynamic speed of an animated slider allowing you to start and stop the animation. In this case, the animation button is only shown in the Graphics View if there is also an animated slider with static (i. e. non-dynamic) speed.
You can use the following operations for Boolean variables and conditions in GeoGebra by either selecting them from the list next to the Input Bar or by entering them using the keyboard:
|
List |
Keyboard |
Example |
Object types |
Equal |
≟ |
== |
a ≟ b or a == b |
numbers, points, lines, conics a, b |
Unequal |
≠ |
!= |
a ≠ b or a != b |
numbers, points, lines, conics a, b |
Less than |
< |
< |
a < b |
numbers a, b |
Greater than |
> |
> |
a > b |
numbers a, b |
Less or equal than |
≤ |
<= |
a ≤ b or a <= b |
numbers a, b |
Greater or equal than |
≥ |
>= |
a ≥ b or a >= b |
numbers a, b |
And |
∧ |
&& |
a ∧ b or a && b |
Booleans a, b |
Or |
∨ |
|
| |
a ∨ b or a || b |
Booleans a, b |
Not |
¬ |
! |
¬a or !a |
Boolean a |
Parallel |
∥ |
|
a ∥
b |
lines a, b |
Perpendicular |
⊥ |
|
a ⊥ b |
lines a, b |