2.3.1.2 Gradient in Spherical Coordinates The gradient in spherical coordinates is defined analogously to the gradient in cylindrical coordinates; that is, we start with the gradient in Cartesian coordinates [Eq. (2.33)] and transform the partial derivatives, unit vectors, and variables from Cartesian to spherical coordinates. Although we will not perform all details of the derivation here (see Exercise 2.5), the important steps are as follows: