**Learning objectives**

- Describe the difference between a constrained and an unconstrained optimization problem
- Give a graphical explanation of the method of Lagrange multipliers
- Give the practical meaning of a Lagrange multiplier

**Before class**

- Read Hughes-Hallett 9.6.
- Ponder problems 9.6. 11-13, 18-21.
- Consult the main points of the lesson

**In class**

- Constraints activity
- Problems
- Work with Lagrange multipliers