Hope this tutorial video is useful for you who would like to learn Matlab and GNU Octave, and please let me know if you have any questions and comments!
Thanks very much. I tried the problem you gave at the end: >> roots([1 -5 5 5 -6]) ans = 3.0000 -1.0000 2.0000 1.0000 I also got complex roots (for x^2 + 1 = 0): >> roots([1 0 1]) ans = -0 + 1i 0 - 1i