Given A=(1234)A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}A=(1324), what is the characteristic equation?
λ2−5λ−2=0\lambda^2 - 5\lambda - 2 = 0λ2−5λ−2=0
λ2+5λ−2=0\lambda^2 + 5\lambda - 2 = 0λ2+5λ−2=0
λ2−5λ+2=0\lambda^2 - 5\lambda + 2 = 0λ2−5λ+2=0
λ2+5λ+2=0\lambda^2 + 5\lambda + 2 = 0λ2+5λ+2=0