CS Degree Day 79

What I did today?

• Lecture 7: Determinants
• Lecture 8: Eigenvalues and eigenvectors
• Problem set: Find eigenvalues and eigenvectors of 2×2 and 3×3 matrices

Interesting things I came across

An eigenvector of a matrix A is a vector v such that Av = λv. The matrix scales the vector by λ but doesn’t change its direction. These special directions are where the transformation is simplest - pure scaling. The PageRank algorithm is an eigenvector computation. The principal components in PCA are eigenvectors. Google’s search rankings emerge from the same mathematics as the vibration modes of a guitar string.