Difference between revisions of "Lines and Axes"
From GeoGebra Manual
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==Lines== | ==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. | + | 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.}} | {{note|You can enter a line’s name at the beginning of the input followed by a colon.}} | ||
{{example|1=<br/> | {{example|1=<br/> | ||
| − | * Type in <code>g: 3x + 4y = 2</code> to enter line g as a linear equation. | + | * Type in <code>g: 3x + 4y = 2</code> to enter line ''g'' as a linear equation. |
| − | * You can enter a line in parametric form thus: | + | * You can enter a line in parametric form thus: <code>g: X = (-5, 5) + t (4, -3)</code> |
| − | * Define the parameters m = 2 and b = -1. Then, you can enter the equation | + | * Define the parameters ''m'' = 2 and ''b'' = -1. Then, you can enter the equation <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|1=The command <code>[[PerpendicularLine Command|PerpendicularLine]][A, xAxis]</code> constructs the perpendicular line to the x-axis through a given point A. }} | {{example|1=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 10:27, 26 September 2012
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 = 2to enter line g as a linear equation. - You can enter a line in parametric form thus:
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 + bto 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
