Sherman–Morrison formula

The Sherman-Morrison formula is a tool to help you figure out the inverse of a matrix when you are given some information about the matrix. It's like an equation that tells you how to rearrange the numbers or letters in a jumble so you can make a new jumble with all the same letters. If you start with a jumble of letters and numbers, like [1, 2, 3, 4], the Sherman-Morrison formula tells you how to rearrange those numbers so you can get [4, 3, 2, 1] or any other combination.