12. What are the eigenvalues of the matrix
| A. {-5, 1} | B. {-1, 5} | C. {-4,-2} | D. {1, 3} | E.{ 2+i sqrt(7) , 2 - i sqrt(7) |
Solution: The answer is B.
The eigenvalues of the general 2 x 2 matrix
are the roots of the polynomial
So, in this case the eigenvalues are the roots
of
That is, the eigenvalues are -1 and 5.