Vandermonde matrix

In this post, we will compute a classical determinant called the Vandermonde determinant. Though the computation of this determinant looks intractable at first, there turns out to be a beautiful formula for it, with a very neat proof. Somewhat surprisingly, the matrices involved and this result are related to the notion of Lagrange interpolating polynomials. … Continue reading Vandermonde matrix

Matrix multiplication

How do you multiply matrices? I realized that the technique that I learned back in the days is not as common as I thought. I often see my students struggling to perform simple matrix multiplications, and I would argue that part of the reason is that they write them side-by-side. This is also what I … Continue reading Matrix multiplication