16-Oct-2013


1> (-1)^(1/3)
ans =  0.50000 + 0.86603i


2> i^2
ans = -1


3> x = linspace(1-1.e-5,1+1.e5);


4> plot(x, (1-x).^3)


5> x = linspace(1-1.e-5,1+1.e-5);


6> plot(x, (1-x).^3)


7> hold on


8> plot(x, 1 - 3*x + 3*x.^2 - x.^3, 'r')


9> hold off


10> (1 + 2*i)/(4 + 3*i)
ans =  0.40000 + 0.20000i


11> z = 4 + 3*i
z =  4 + 3i


12> z = 4 + 3i
z =  4 + 3i


13> real(z)
ans =  4


14> imag(z)
ans =  3


15> abs(z)
ans =  5


16> conj(z)
ans =  4 - 3i


17> help conj
'conj' is a built-in function

 -- Mapping Function:  conj (Z)

     Return the complex conjugate of Z, defined as `conj (Z)' = X - IY.



     See also: real, imag






Additional help for built-in functions and operators is
available in the online 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.


18> compass(z)


19> grid on


20> w = complex(1,2)
w =  1 + 2i


21> hold on


22> compass(w, 'r')


23> compass(z + w, 'g')


24> compass(z - w, 'k')


25> cart2polar(4,3)
error: 'cart2polar' undefined near line 25 column 1


25> help cart2polar
error: help: 'cart2polar' not found


25> help polar2cart
'polar2cart' is a function from the file C:\cygwin\home\achilles\polar2cart.m

 polar2cart

Additional help for built-in functions and operators is
available in the online 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.


26> help cart2pol
'cart2pol' is a function from the file C:\Octave\Octave3.6.4_gcc4.6.2\share\octave\3.6.4\m\general\cart2pol.m

 -- Function File: [THETA, R] = cart2pol (X, Y)

 -- Function File: [THETA, R, Z] = cart2pol (X, Y, Z)

 -- Function File: [THETA, R] = cart2pol (C)

 -- Function File: [THETA, R, Z] = cart2pol (C)

 -- Function File: P = cart2pol (...)

     Transform Cartesian to polar or cylindrical coordinates.



     THETA describes the angle relative to the positive x-axis.  R is

     the distance to the z-axis (0, 0, z).  X, Y (and Z) must be the

     same shape, or scalar.  If called with a single matrix argument

     then each row of C represents the Cartesian coordinate (X, Y (,

     Z)).



     If only a single return argument is requested then return a matrix

     P where each row represents one polar/(cylindrical) coordinate

     (THETA, PHI (, Z)).



     See also: pol2cart, cart2sph, sph2cart






Additional help for built-in functions and operators is
available in the online 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.


27> cart2pol(4,3)
error: 'z' undefined near line 79 column 24
error: called from:
error:   C:\Octave\Octave3.6.4_gcc4.6.2\share\octave\3.6.4\m\general\cart2pol.m at line 79, column 11


27> [theta, rho] = cart2pol(4,3)
theta =  0.64350
rho =  5


28> theta_in_gradi = theta * 180/pi
theta_in_gradi =  36.870


29> help pol2cart
'pol2cart' is a function from the file C:\Octave\Octave3.6.4_gcc4.6.2\share\octave\3.6.4\m\general\pol2cart.m

 -- Function File: [X, Y] = pol2cart (THETA, R)

 -- Function File: [X, Y, Z] = pol2cart (THETA, R, Z)

 -- Function File: [X, Y] = pol2cart (P)

 -- Function File: [X, Y, Z] = pol2cart (P)

 -- Function File: C = pol2cart (...)

     Transform polar or cylindrical to Cartesian coordinates.



     THETA, R, (and Z) must be the same shape, or scalar.  THETA

     describes the angle relative to the positive x-axis.  R is the

     distance to the z-axis (0, 0, z).  If called with a single matrix

     argument then each row of P represents the polar/(cylindrical)

     coordinate (X, Y (, Z)).



     If only a single return argument is requested then return a matrix

     C where each row represents one Cartesian coordinate (X, Y (, Z)).



     See also: cart2pol, sph2cart, cart2sph






Additional help for built-in functions and operators is
available in the online 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.


30> [a, b] = plo2cart(theta, rho)
error: 'plo2cart' undefined near line 30 column 11


30> [a, b] = pol2cart(theta, rho)
a =  4
b =  3


31> angle(z)
ans =  0.64350


32> theta
theta =  0.64350


33> 0/0
ans = NaN


34> 1/0
ans = Inf


35> -1/0
ans = -Inf


36> Inf/Inf
ans = NaN


37> a
a =  4


38> A = 5
A =  5


39> a
a =  4


40> A
A =  5


41> a2 = 7
a2 =  7


42> 2a = 8
parse error:

  syntax error

>>> 2a = 8
      ^



42> esempio
error: 'esempio' undefined near line 42 column 1


42> % esempio


42> # esempio


42> quit