Definition: A linear inequality in 2 variables is a linear equation in 2 variables in which the "=" has been replaced by an inequality.

Regulation: The solution set of a linear inequality is a region in the plane bounded by the line of the corresponding linear equation. (This set includes the points on the line only if inequality includes the equals sign, i.e. is not a strict inequality).
Examples of linear inequalities in 2 variables: \bbox[border:1px #990000 dotted,1pt]{y>2x-3}   \bbox[border:1px #990000 dotted,1pt]{2y+5x \leq 2}   \bbox[border:1px green dotted,1pt]{3s<2t-2}
InterActivity    Directions for InterActivity  Menu with 4 InterActivities (new window)
   

Goal: Get familiar with the graph of a linear inequality in 2 variables - a region in the plane bounded by a solid or dashed line.


1. In the input box below, type or paste in a linear inequality in 2 variables x and y. Hit Enter and view the resulting region in the plane.
* You can type <= for  and  >= for .


(Samples: 3x+2y>=1, y>4x/5-11/5, 0.2x-0.5y≤2, ...)


2. To change the view, click on the Move tool Move Graphics View and then click and drag the graph as desired.


• Note whether the line is solid or dashed depends on whether "equality" is included in the inequality.


3. Find the coordinates of any point in the shaded region and substitute its coordinates into the inequality. The inequality should be "true".


4. Find the coordinates of any point NOT in the shaded region and substitute its coordinates into the inequality. The inequality should be "false".


• To start over, enter a new inequality and hit Enter.

Linear Inequality:  
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Many thanks to mathmagic and piman!      LFS , Created with GeoGebra

Related Topics

Metadata
Global Graphing Linear Inequalities in 2 Variables
Brief InterActivity for graphing 1 or 2 linear inequalities in 2 variables
Grade 8th and up (must know how to graph lines)
Strand Algebra 1 - 2 AF at Math247
Standard Algebra 1 2.2   CA Algebra 2 2.0   ACT GR 28-32   ACT GR 33-36
Keywords linear, inequality, system, 2 variables, algebra, dynamic, freeware, applet, offline, online
Comments Hopefully a reverse inactivity coming soon.
Credits David Cox for asking; MathMagic and Piman of the GeoGebra forum for creating the algorithm!
Download

|(:cell PQA(PSS():)Zip - Completely Offline & School

Author LFS - contact
Type Freeware - Available for Offline and Online Use - Translatable (html)
Use Requires sunJava player

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Page last modified on September 09, 2009, at 05:25 AM