# Solving simultaneous equations for mesh analysis

#### bendi

Joined Jan 1, 2011
1
Hi
Can anybody advise whether there is an online or down-loadable calculator for mesh analysis solving complex notation such as a + jb using determinants and calculating for two or three unknown variables? Thanks in advance.

Mark (Bendi)

#### blah2222

Joined May 3, 2010
582
Matlab will do it.

Joined Feb 16, 2010
112
Also, Octave is a free command-line version of MATLAB which will probably do it. Does anyone know if a TI-89 will do it? I've never tried rref() with matrices containing complex numbers.

#### t06afre

Joined May 11, 2009
5,934
The HP graphics calculators will do it.

Joined Jul 7, 2009
1,583
You can do it with python and scipy which are freely downloadable tools:

Rich (BB code):
from scipy import *
from scipy import linalg

A = mat("[1 3 5; 2+1j 5 1; 2 3 8]")
b = mat("[10;8;3]")
print A.I*b   # .I means to take the inverse
print linalg.solve(A, b)
(note the complex number in the second row of the matrix) which produces

Rich (BB code):
[[-8.21529745+2.95750708j]
[ 5.39660057+0.6572238j ]
[ 0.40509915-0.98583569j]]
[[-8.21529745+2.95750708j]
[ 5.39660057+0.6572238j ]
[ 0.40509915-0.98583569j]]
The example shows both matrix inversion and a linear equation solver (the solver is preferable because it is numerically more stable).

#### guitarguy12387

Joined Apr 10, 2008
359
TI-89 will do it!

#### victorhugo289

Joined Aug 24, 2010
49
You'll definitely might want to look at Qalculate, it's a calculator for Linux, i use it on Ubuntu all the time, I managed to overwrite the ABC.. constants that have been programmed into it and I used them as XYZ variables so I can solve any equation that uses ABCD..etc variables.
It solves for values, it factorizes, it simplifies, it's amazing.
I use it only for simple Algebra, but you can definitely solve the complicated stuff in there.