1
$\begingroup$

If $A = \begin{bmatrix} 2 & k \\ 0 & 1 \end{bmatrix}$. Find all values of $k$ for which A has eigenvalues 3 and -1. A has no real eigenvalues. (David Poole, Linear Algebra).

The characteristic equation $(2 - \lambda)(1 - \lambda) = 0$ doesn't depend on $k$, so is this ever true? What am I missing here?

$\endgroup$
  • $\begingroup$ There might be typo in your matrix $A$; the lower left corner is $1$ and not $0$. $\endgroup$ – Dietrich Burde May 25 '16 at 11:29
  • $\begingroup$ Well, that seems to be the best logical conclusion. Textbook typos hurt bad. $\endgroup$ – buzaku May 25 '16 at 11:42
1
$\begingroup$

The matrix you wrote down always has two eigenvalues, $2$ and $1$.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.