- #1
SherlockOhms
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Homework Statement
For which values of x is the matrix (see attachment) invertible?
Homework Equations
Row ops. Cofactors etc..
The Attempt at a Solution
Well, a matrix is only invertible when it's determinant is non zero. I've begun doing some row ops and have just hit a little snag. If you look at the attachment you'll see that I can facto (1 - x) out from the minor matrix. I remember hearing in a lecture that you have to factor out (1 - x) from both the top and bottom row of the matrix (i.e. you'll have (1 -x)^2 factored out instead of just (1 - x). Could somebody explain why you don't just factor out (1 - x) one like you would with factoring a scalar out of a matrix as normal?x