Difference between revisions of "Lines and Axes"
From GeoGebra Manual
(added v.4) |
m |
||
Line 5: | Line 5: | ||
{{note|You can enter a line’s name at the beginning of the input followed by a colon.}} | {{note|You can enter a line’s name at the beginning of the input followed by a colon.}} | ||
− | {{example| | + | {{example|1=<br/> |
− | * Type in <code | + | * Type in <code>g: 3x + 4y = 2</code> to enter line g as a linear equation. |
− | * Define a parameter t (e. g., | + | * Define a parameter t (e. g., t = 3) before entering line g in parametric form using<br><code>g: X = (-5, 5) + t (4, -3)</code>. |
− | * Define the parameters | + | * Define the parameters m = 2 and b = -1. Then, you can enter the equation<br><code>h: y = m*x + b</code> to get a line h in y-intercept-form.}} |
==Axes== | ==Axes== | ||
The two coordinate axes are available in commands using the names xAxis and yAxis. | The two coordinate axes are available in commands using the names xAxis and yAxis. | ||
{{example|The command <code>[[PerpendicularLine Command|PerpendicularLine]][A, xAxis]</code> constructs the perpendicular line to the x-axis through a given point A. }} | {{example|The command <code>[[PerpendicularLine Command|PerpendicularLine]][A, xAxis]</code> constructs the perpendicular line to the x-axis through a given point A. }} |
Revision as of 15:58, 18 April 2011
Lines
You can enter a line as a linear equation in x and y or in parametric form into the Input Bar. In both cases previously defined variables (e. g. numbers, points, vectors) can be used within the equation.
Note: You can enter a line’s name at the beginning of the input followed by a colon.
Example:
- Type in
g: 3x + 4y = 2
to enter line g as a linear equation. - Define a parameter t (e. g., t = 3) before entering line g in parametric form using
g: X = (-5, 5) + t (4, -3)
. - Define the parameters m = 2 and b = -1. Then, you can enter the equation
h: y = m*x + b
to get a line h in y-intercept-form.
Axes
The two coordinate axes are available in commands using the names xAxis and yAxis.
Example: The command
PerpendicularLine[A, xAxis]
constructs the perpendicular line to the x-axis through a given point A. Comments
Get parameters of a line[edit]
From the line a: 2.2 x + 3.3 y = 4.4
you'll get with
x(a)
the value 2.2y(a)
the value 3.3z(a)
the value -4.4 (because GeoGebra save the line equation as2.2 x + 3.3 y - 4.4 = 0
.
More informations: Coefficients Command