# Removing Equality Constraints

Learn to solve optimization problems with equality constraints.

## We'll cover the following

We’re going to learn about **good constraints**. Those are constraints that make our lives easier.

## Getting started with equality constraints

Remember the problem of finding the smaller surface of the soda cans? Here’s the problem formulation:

$\min_{r, h} 2\pi rh + 2\pi r^2 \\ s.t.: \pi r^2h = 355$

That constraint was helpful. We knew how to deal with the target functions of one variable and the constraint helped us to get rid of variable $h$.

We used the constraint to make $h$ a function of $r$:

$h = \frac{355}{\pi r^2}$

Then we transformed the target function accordingly:

$\min_{r} 2\pi r\frac{355}{\pi r^2} + 2\pi r^2$

We transformed a multivariate constrained problem into a univariate unconstrained one. A pretty good deal!

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