This chapter demonstrates how to find partial derivatives of functions using SymPy, focusing on functions involving two variables. We illustrate the construction of a Jacobian matrix composed of partial derivatives and a Hessian matrix comprising second-order derivatives. In addition, this chapter presents two applications for determining local minima and maxima using derivatives: one utilising the Hessian matrix and the other employing the Lagrange method. The chapter concludes with an introduction to computing double integrals using SymPy.