# How do I find the given eigenvectors

3 views (last 30 days)
kimi on 16 Nov 2020
Answered: Athul Prakash on 19 Nov 2020
Hello,
I have a 8x8 identity eigenvalue matrix (ss) and the answer 4x8 eigenvector matrix (ivect). I'm unsure of the process to get to the eigenvector matrix.
>> ss
ss =
1.0e+02 *
Columns 1 through 5
0.0000 + 2.7894i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 - 2.7894i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i -0.0000 + 1.9015i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i -0.0000 - 1.9015i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i -0.0000 + 1.3474i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
Columns 6 through 8
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i 0.0000 + 0.0000i
-0.0000 - 1.3474i 0.0000 + 0.0000i 0.0000 + 0.0000i
0.0000 + 0.0000i -0.0000 + 1.4094i 0.0000 + 0.0000i
0.0000 + 0.0000i 0.0000 + 0.0000i -0.0000 - 1.4094i
ivect =
1.0e+02 *
Columns 1 through 5
0.0100 + 0.0000i 0.0100 + 0.0000i 0.0100 + 0.0000i 0.0100 + 0.0000i 0.0100 + 0.0000i
0.0000 - 0.0011i 0.0000 + 0.0767i 0.0000 - 0.0097i 0.0000 + 0.0112i 0.0000 + 0.0011i
0.0000 - 0.0040i 0.0000 + 0.0645i 0.0000 + 0.2500i 0.0000 - 1.0500i 0.0000 + 0.0040i
-0.0097 + 0.0000i 0.0183 + 0.0000i 0.2850 + 0.0000i 0.9660 + 0.0000i -0.0097 + 0.0000i
Columns 6 through 8
0.0100 + 0.0000i 0.0100 + 0.0000i 0.0100 + 0.0000i
0.0000 - 0.0767i 0.0000 + 0.0097i 0.0000 - 0.0112i
0.0000 - 0.0645i 0.0000 - 0.2500i 0.0000 + 1.0500i
0.0183 + 0.0000i 0.2850 + 0.0000i 0.9660 + 0.0000i

Athul Prakash on 19 Nov 2020
I presume that you've obtained these eigenvalues by calling the 'eig' function in MATLAB. You may try calling the same with a second output argument to obtain corresponding eigenvectors as well -
[A,B] = eig(m1);
I suggest going through the documentation of 'eig' for a fuller understanding, if requried - The exmaples, in particular, may be useful.
Hope it Helps!