Difference between revisions of "Inequalities"
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− | To graph inequalities of the form | + | To graph inequalities of the "less than" form |
− | + | "ax + by + c <= 0" | |
− | |||
<source lang="javascript"> | <source lang="javascript"> | ||
− | line = | + | var line = board.create('line', [c, b, a]), |
− | ineq = | + | ineq = board.create('inequality', [line]); |
</source> | </source> | ||
− | + | ||
− | If one wants to show "greater than", ''inverse:true'' has to be used: | + | If one wants to show "greater than" i.e. "ax + by + c >= 0" , ''inverse:true'' has to be used: |
<source lang="javascript"> | <source lang="javascript"> | ||
− | line = | + | var line = board.create('line', [c, b, a]), |
− | ineq = | + | ineq = board.create('inequality', [line], {inverse:true}); |
</source> | </source> | ||
In the following example, two lines are shown. | In the following example, two lines are shown. | ||
− | The first, | + | The first, blue line has the equation "y = 2x + 3" or "2x - 1y + 3 = 0", |
− | the second, | + | the second, black line has the equation "x = 3" or "1x + 0y - 3 = 0". |
− | + | For these equations, the inequalities plotted are | |
− | + | "2x - y + 3 <= 0" (less than form hence don't add "inverse: true") - yellow region | |
+ | and | ||
+ | "1x + 0y - 3 >= 0" (greater than form hence do add "inverse: true") - red region. | ||
<jsxgraph width="400" height="400" box="box1"> | <jsxgraph width="400" height="400" box="box1"> | ||
(function() { | (function() { | ||
− | var b = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 5, 5, -5], axis:true}); | + | var b = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 5, 5, -5], axis:true}); |
− | var | + | var line1 = b.create('line', [3, 2, -1]), // Line y = 2x + 3 or 2x - 1y + 3 = 0 |
− | + | ineq1 = b.create('inequality', [line1], {fillColor: 'yellow'}); //This would plot the inequality 2x - y + 3 <= 0 | |
− | ineq1 = b.create('inequality', [line1], { | ||
− | line2 = b.create('line', [1, | + | var line2 = b.create('line', [-3, 1, 0], {strokeColor: 'black'}); // Line x = 3 or 1x + 0y - 3 = 0 |
− | ineq2 = b.create('inequality', [line2], {fillColor: ' | + | var ineq2 = b.create('inequality', [line2], {inverse: true, fillColor: 'red'}); //This would plot the inequality 1x + 0y - 3 >= 01x + 0y - 3 >= 0 |
})(); | })(); | ||
Line 35: | Line 35: | ||
===The JavaScript code=== | ===The JavaScript code=== | ||
<source lang="javascript"> | <source lang="javascript"> | ||
− | var | + | var board = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 5, 5, -5], axis:true}); |
− | var | + | var line1 = board.create('line', [3, 2, -1]), // Line y = 2x + 3 or 2x - 1y + 3 = 0 |
− | + | ineq1 = board.create('inequality', [line1], {fillColor: 'yellow'}); //This would plot the inequality 2x - y + 3 <= 0 | |
− | |||
− | |||
− | |||
− | |||
+ | var line2 = board.create('line', [-3, 1, 0], {strokeColor: 'black'}); // Line x = 3 or 1x + 0y - 3 = 0 | ||
+ | var ineq2 = board.create('inequality', [line2], {inverse: true, fillColor: 'red'}); //This would plot the inequality 1x + 0y - 3 >= 0 | ||
</source> | </source> | ||
[[Category:Examples]] | [[Category:Examples]] | ||
[[Category:Calculus]] | [[Category:Calculus]] |
Latest revision as of 11:57, 8 June 2017
To graph inequalities of the "less than" form "ax + by + c <= 0"
var line = board.create('line', [c, b, a]),
ineq = board.create('inequality', [line]);
If one wants to show "greater than" i.e. "ax + by + c >= 0" , inverse:true has to be used:
var line = board.create('line', [c, b, a]),
ineq = board.create('inequality', [line], {inverse:true});
In the following example, two lines are shown. The first, blue line has the equation "y = 2x + 3" or "2x - 1y + 3 = 0", the second, black line has the equation "x = 3" or "1x + 0y - 3 = 0".
For these equations, the inequalities plotted are "2x - y + 3 <= 0" (less than form hence don't add "inverse: true") - yellow region and "1x + 0y - 3 >= 0" (greater than form hence do add "inverse: true") - red region.
The JavaScript code
var board = JXG.JSXGraph.initBoard('box1', {boundingbox: [-5, 5, 5, -5], axis:true});
var line1 = board.create('line', [3, 2, -1]), // Line y = 2x + 3 or 2x - 1y + 3 = 0
ineq1 = board.create('inequality', [line1], {fillColor: 'yellow'}); //This would plot the inequality 2x - y + 3 <= 0
var line2 = board.create('line', [-3, 1, 0], {strokeColor: 'black'}); // Line x = 3 or 1x + 0y - 3 = 0
var ineq2 = board.create('inequality', [line2], {inverse: true, fillColor: 'red'}); //This would plot the inequality 1x + 0y - 3 >= 0