Hi all.

Just wondering if I could get some tips on how to find eigenvalues for 3x3 matrices by row/column expansion. We've been taught to set all but one entries of a row or column to zero, then for that non-zero entry use it to find the other eigenvalues via the smaller 2x2 determinant. I'm having a hard time with this initial step though and often I rely on just guessing row/column operations until I get the values I need. This is too time consuming to do in an exam situation so I was wondering, are there any things I should be looking out for, or is this something that I will only be able to improve on with constant practice.

Cheers.