MATLAB is a computer program for doing numerical calculations. It is available on all the EE and TCC computers on campus. A Windows version of MATLAB is available to students to put on their personal computers - see your professor or Chris Langley to find out how to get this program. If you run Linux, Windows 95 or Windows NT on your computer there is a program called Octave which does most of the things MATLAB does, and will do all the analyses you need for this course. You can download Octave from http://www.che.wisc.edu/octave/octave.html.

To solve multiple equations using MATLAB (or Octave) write the equations with all the unkowns on the left hand side and the knowns on the right hand side: for example,

To solve this equation in MATLAB type the folowing commands:

A = [ 0.0020 -0.0020 -0.0010; -0.0020 0.0015 0.0000; -0.0020 0.0000 0.0020] b = [ 0.005; 0.005; -0.005] v = A\b

The result will be

v = 6.4000 5.6000 2.2000

This means that *v*_{A} = 6.4V, *v*_{B} = 5.6V and *v*_{C} = 2.2V.

Note: MATLAB will only solve numeric equations.

Suppose you had a set of equations which looked like this:

where *R*_{1} = 1k,
*R*_{2} = 1k,
*R*_{3} = 2k,
*R*_{4} = 1k,
*i*_{S1} = 5mA, and
*i*_{S2} = 2mA. Then, to reduce the chance of error, you
could let MATLAB find the coefficients before solving:

G1 = 1/1e3; G2 = 1/1e3; G3 = 1/2e3; G4 = 1/1e3; i1 = 5e-3; i2 = 2e-3; A = [G1+G2 -G1 -G2; -G1 G1+G3 0; -G2 0 G2+G4] b = [i1; i2; -i2] v = A\b

The answer is

v = 6.4000 5.6000 2.2000

which means *v*_{A} = 6.4V, *v*_{B} = 5.6V and *v*_{C} = 2.2V.