# Vectors and Covectors

Covectors are dual to vectors, and they’re fundamental to understand differential forms and tensors.

Up to this point in the Lagrangian arc, we’ve been looking at the paths objects take through space. These paths are functions of time that output positions in space. As we continue through this series, we’ll want to look at functions of space and time. More specifically, we’ll want to take derivatives and integrals of these functions with respect to our coordinates in space.

While we have taken these spatial derivatives in the PDE arc, we’ve only worked in Cartesian and spherical coordinates. Even then, we had to use a lot of facts without explanation or derivation, such as the form of the Laplacian in spherical coordinates.

Over the next few articles, we’re going to fix those problems by coming up with a way to take these derivatives and integrals in arbitrary coordinates.

# Check Your Understanding

We’re doing formalism in this article, so checking your understanding requires that you practice working with the formalism yourself.