A characteristic polynomial

ComputeThe characteristic polynomial

Find the characteristic polynomial $p(t) = \det(A - tI)$ of

A = \begin{pmatrix} 1 & 2 \\ 2 & 1 \end{pmatrix}.

Give your answer as a polynomial in $t$ .

Enter an expression. Any equivalent form is accepted.

A characteristic polynomial · Proofwise

ComputeThe characteristic polynomial

Find the characteristic polynomial $p(t) = \det(A - tI)$ of

A = \begin{pmatrix} 1 & 2 \\ 2 & 1 \end{pmatrix}.

Give your answer as a polynomial in $t$ .

Enter an expression. Any equivalent form is accepted.