1> t = linspace(0, 2*pi);

2> size(t)
ans =

     1   100


3> x = cos(t); y = sin(t);

4> A = [3 2; 2 3]
A =

   3   2
   2   3


5> z = A * [x; y];

6> size(z)
ans =

     2   100


7> plot(x,y)

8> axis equal

9> 

9> hold on

10> plot(z(1,:), z(2,:), 'r')

11> [autovettori, lambda] = eig(A)
autovettori =

  -0.70711   0.70711
   0.70711   0.70711

lambda =

Diagonal Matrix

   1   0
   0   5


12> x1 = autovettori(:,1)
x1 =

  -0.70711
   0.70711


13> x5 = autovettori(:,2)
x5 =

   0.70711
   0.70711


14> plot([0,x1(1)], [0,x1(2)], 'b')

15> plot([0,x5(1)], [0,x5(2)], 'r')

16> % codice per il metodo delle potenze

16> help metpot
`metpot' is a function from the file /home/achilles/metpot.m

 metodo delle potenze

Additional help for built-in functions and operators is
available in the on-line version of the manual.  Use the command
`doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at http://www.octave.org and via the help@octave.org
mailing list.

17> [lambda, y] = metpot(A, [-1; 1])
lambda =  5.0000
y =

  -0.70711
  -0.70711


18> help cerchio
`cerchio' is a function from the file /home/achilles/cerchio.m

 plot di un cerchio di 
 centro c (numero complesso) e di raggio r

Additional help for built-in functions and operators is
available in the on-line version of the manual.  Use the command
`doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at http://www.octave.org and via the help@octave.org
mailing list.

19> hold off

20> cerchio(i,4)

21> grid on

22> hold off

23> gersh(A)

24> A
A =

   3   2
   2   3


25> B = [i-2 4+3i 5i; 2i+5 7i 3; 2i+3 3 -i]
B =

  -2 + 1i   4 + 3i   0 + 5i
   5 + 2i   0 + 7i   3 + 0i
   3 + 2i   3 + 0i  -0 - 1i


26> gersh(B)

27> hold off

28> gersh(B)

29> % per calcolare l'autovalore 1 di A con lo shift -5

29> metpot(A-5*eye(2,2),ones(2,1))
warning: division by zero
ans = NaN

30> metpot(A-5*eye(2,2),[2;4])
ans = -4.0000

31> quit