### Author Topic: Ejs open source Linear Equation Interactive Java Applet  (Read 16764 times)

#### lookang

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##### Ejs open source Linear Equation Interactive Java Applet
« on: January 19, 2009, 11:23:33 am »
Open source Ejs Linear Equation Interactive Java Applet
Linear Equation created by Wee Loo Kang (Good!)
http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=546.msg1806#msg1806
http://home.phy.ntnu.edu.tw/~lookang/EJS_4.1_090115/weelookanglinear_Simulation.html
Ejs open source

Full screen applet or Problem viewing java?Add http://www.phy.ntnu.edu.tw/ to exception site list
• Please feel free to post your ideas about how to use the simulation for better teaching and learning.
• Post questions to be asked to help students to think, to explore.
• Upload worksheets as attached files to share with more users.
Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!
« Last Edit: May 06, 2011, 04:36:58 pm by lookang »

#### lookang

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##### Re: Open source Ejs Linear Equation Interactive Java Applet
« Reply #1 on: June 18, 2009, 01:18:08 pm »
customize from an earlier source code by Hwang Fu-Kwun
06May 2011
add Length = Math.sqrt( ( y2-y1) + (x2-x1) ) for the learning of length of segment
add input field and options to draw green line

it just hit me that i will be cool, if an option to

input the equation and it show the line on the drawing panel! Got time will improve it Done!

Just found
Step by Step Graphing of Absolute Value Equations (Linear & Quadratic)Jump to: navigation, searchUse this applet to demonstrate and visualize how to sketch graphs of absolute valued functions containing linear or quadratic terms. Suitable for pupil self learning as well

Sketching Graphs of Absolute Valued Functions(with linear or quadratic terms) Step by Step Approach

Feel free to modify it. Do appreciate your feedback to lewweisern@gmail.com

« Last Edit: May 06, 2011, 04:53:48 pm by lookang »

#### lookang

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##### Re: Ejs open source Linear Equation Interactive Java Applet
« Reply #2 on: May 06, 2011, 11:17:02 am »
not sure why but there is an error?

Java Plug-in 1.6.0_20
Using JRE version 1.6.0_20-b02 Java HotSpot(TM) Client VM
User home directory = C:Documents and Settings
----------------------------------------------------
c: clear console window
f: finalize objects on finalization queue
g: garbage collect
h: display this help message
m: print memory usage
o: trigger logging
q: hide console
s: dump system and deployment properties
0-5: set trace level to
----------------------------------------------------

java.lang.reflect.InvocationTargetException
at java.awt.EventQueue.invokeAndWait(Unknown Source)
at javax.swing.SwingUtilities.invokeAndWait(Unknown Source)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationView.(LinearEquationView.java:188)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationSimulation.(LinearEquationSimulation.java:20)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquation.(LinearEquation.java:93)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationApplet.init(LinearEquationApplet.java:26)
at sun.plugin2.applet.Plugin2Manager\$AppletExecutionRunnable.run(Unknown Source)
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkConnect(Unknown Source)
at sun.plugin2.applet.Applet2SecurityManager.checkConnect(Unknown Source)
at sun.awt.SunToolkit.getImageFromHash(Unknown Source)
at sun.awt.SunToolkit.getImage(Unknown Source)
at javax.swing.ImageIcon.(Unknown Source)
at javax.swing.ImageIcon.(Unknown Source)
at org.colos.ejs.library.control.swing.ControlSwingElement.getIcon(Unknown Source)
at org.colos.ejs.library.control.ControlElement.setProperty(Unknown Source)
at org.colos.ejs.library.control.ControlElement.setProperty(Unknown Source)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationView.createControl50(LinearEquationView.java:1360)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationView.createControl(LinearEquationView.java:1206)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationView.access\$000(LinearEquationView.java:19)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationView\$1.run(LinearEquationView.java:190)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
java.lang.NullPointerException
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationView.reset(LinearEquationView.java:1653)
at org.colos.ejs.library.Animation.reset(Unknown Source)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationSimulation.(LinearEquationSimulation.java:24)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquation.(LinearEquation.java:93)
at users.sgeducation.lookang.LinearEquation_pkg.LinearEquationApplet.init(LinearEquationApplet.java:26)
at sun.plugin2.applet.Plugin2Manager\$AppletExecutionRunnable.run(Unknown Source)
Exception: java.lang.NullPointerException

#### lookang

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##### Re: Ejs open source Linear Equation Interactive Java Applet
« Reply #3 on: May 06, 2011, 01:20:51 pm »
not to worry!
the error is a result of using Ejs 4.3.0
i used Ejs 4.3.3.1 and it is ok now
enjoy!

#### ahmedelshfie

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##### Re: Ejs open source Linear Equation Interactive Java Applet
« Reply #4 on: May 06, 2011, 06:11:22 pm »
Do you mean when use diffrent Ejs version can have error i already use last version and also ejs 4.3.0 but didn't have errors when run or recompile to jar file.
However seems error that you got is between JDK (Java Plug) may if you set the right path to jdk in your PC can solve it also you can know the path of jdk using command
start>>cmd>>set Java_Home, to can watch the right path.

#### lookang

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##### Re: Ejs open source Linear Equation Interactive Java Applet
« Reply #5 on: May 06, 2011, 06:51:37 pm »
Web deploy didn't work on 4.3
The jar runs perfectly that is why need to check web version

#### ahmedelshfie

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##### Re: Ejs open source Linear Equation Interactive Java Applet
« Reply #6 on: May 06, 2011, 08:51:34 pm »
I suggest you uninstall and install again JDK, may this solve the probelm.

#### geeknick

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• Posts: 1
##### Re: Ejs open source Linear Equation Interactive Java Applet
« Reply #7 on: November 10, 2011, 02:28:10 pm »
Is there any java program for solving linear equations or any java applet for that?? Hello! Could you please help me with this? I have my answer but I am not sure. I am also not sure in my solution. Thanks in advance