Check if matrice is invertible, and if so, ﬁnd the inverse. [4×4] I got this matrice here, I have to check if it's invertible, do I need to use a Laplace method for this? For a simple 2×2 matrice which looks like
\begin{bmatrix}a&b\\c&d\end{bmatrix}
it would be ad - bc, if it doesn't equal 0 then it's invertible. But how do I approach the bigger matrices?
\begin{bmatrix}0&1&1&1\\1&0&1&1\\1&1&0&1\\1&1&1&0\end{bmatrix}

As mentioned, use Laplace method for hand calculating determinants for small matrices.
https://en.m.wikipedia.org/wiki/Laplace_expansion
Here you see we can ignore the first term since its entry is zero.
