Difference between revisions of "Lines and Axes"
From GeoGebra Manual
(Created page with '==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, vecto...') |
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==Lines== | ==Lines== | ||
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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.}} | ||
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* Type in <code><nowiki>g: 3x + 4y = 2</nowiki></code> to enter line g as a linear equation. | * Type in <code><nowiki>g: 3x + 4y = 2</nowiki></code> to enter line g as a linear equation. | ||
* Define a parameter t (e. g., <nowiki>t = 3</nowiki>) before entering line g in parametric form using<br><code><nowiki>g: X = (-5, 5) + t (4, -3)</nowiki></code>. | * Define a parameter t (e. g., <nowiki>t = 3</nowiki>) before entering line g in parametric form using<br><code><nowiki>g: X = (-5, 5) + t (4, -3)</nowiki></code>. | ||
| − | * Define the parameters <nowiki>m = 2 and b = -1</nowiki>. Then, you can enter the equation<br><code><nowiki>h: y = m*x + b</nowiki></code> to get a line h in y-intercept-form. | + | * Define the parameters <nowiki>m = 2 and b = -1</nowiki>. Then, you can enter the equation<br><code><nowiki>h: y = m*x + b</nowiki></code> to get a line h in y-intercept-form.}} |
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==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 16:09, 17 December 2010
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. - 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 + 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
