An eigenvalue ($\lambda$) of a square matrix $A$ is a scalar that satisfies the characteristic equation: $ \det(A - \lambda I) = 0 $ where $I$ is the identity matrix of the same dimension as $A$.
We are given that $\lambda = 0$ is an eigenvalue of matrix $A$. Substituting $\lambda = 0$ into the characteristic equation gives:
$ \det(A - 0 \cdot I) = 0 $Simplifying the expression inside the determinant:
$ A - 0 \cdot I = A $Therefore, the characteristic equation becomes:
$ \det(A) = 0 $This shows that if 0 is an eigenvalue of a matrix $A$, its determinant must be 0.
Hence, if $\lambda = 0$ is an eigenvalue of $A$, then $\det(A)$ is 0.