- #1
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What's the best way to take the determinant of a 3 X 3 matrix. It's actually a matrix in the form:
[tex] \mathbf{A} - \lambda\mathbf{I} [/tex]
So I figured Gaussian elimination would be ugly, because of all the lambdas floating around. I tried the method of expansion by cofactors...and ended up with the cubic characteristic polynomial, only to find I had no idea how to solve it. I took that to mean that I had done something wrong, so rather than posting that result, I thought I'd get some advice on how to start from scratch. The matrix is symmetric, btw, if that helps the situation.
[tex] \mathbf{A} - \lambda\mathbf{I} [/tex]
So I figured Gaussian elimination would be ugly, because of all the lambdas floating around. I tried the method of expansion by cofactors...and ended up with the cubic characteristic polynomial, only to find I had no idea how to solve it. I took that to mean that I had done something wrong, so rather than posting that result, I thought I'd get some advice on how to start from scratch. The matrix is symmetric, btw, if that helps the situation.