Next: Examples Up: Systems of First Order Previous: Example   Contents

## Using sys3plot.m

1. Solve the system symbolically (if appropriate).

2. Make the necessary changes in initsys.m. Note that the B matrix must be given some value, even if it is not used. In such cases, the empty matrix is best; i.e., B = []. Choosing the desired symbolicplot option is done by commenting the others out; i.e., putting a % at the beginning of each line containing the undesired options. Save initsys.m then type initsys (or copy-and-paste at the Emporium).

3. Type sys3plot. This may take up to a few minutes depending on your machine and the difficulty of the ODE system. In your Figure window, you should have three plots.
1. Upper right contains Figure 1, the solution plots , generated by MATLAB's ODE45 solver. is the solid line, is the dashed line. Time is the independent variable.
2. Lower right contains Figure 3, the phase plane portrait of vs as generated by MATLAB's ODE 45 solver.
3. Lower left contains Figure 2: (i) The solution plots , generated from your symbolic solution entered as x1symb and x2symb in initsys.m; (ii) the phase plane portrait generated from your symbolic solution entered as x1symb and x2symb in initsys.m; (iii) a plot of the eigenvalues of matrix A; or (iv) nothing. This depends on the selected option for symbolicplot.

4. Make a visual check that the information in all figures and your ``hand work'' match/agree. If all appears correct, print a copy of the display.

5. In the upper left of your printout, neatly and orderly rewrite the work you did for Item 1 (if applicable). If you were not directed to solve the system symbolically, use this area to answer any other questions.

Subsections

Next: Examples Up: Systems of First Order Previous: Example   Contents
Michael Renardy
2000-05-12