Solution
= Solution
Expansion of the <determinant> gives $\det M=-\mu-\mu=-2\mu$. The <matrix inverse> exists precisely when
$$
\boxed{\mu\ne0.}
$$
= Solution
Expansion of the <determinant> gives $\det M=-\mu-\mu=-2\mu$. The <matrix inverse> exists precisely when
$$
\boxed{\mu\ne0.}
$$