(Mathematical, continuous) Optimization?

Unconstrained optimization problem:

$$ \operatorname*{minimize}_{x \in \R^d} \; f(x) $$

Constrained optimization problem:

$$ \begin{aligned} \operatorname*{minimize}_{x \in \R^d} \;\; & f(x) \\ \text{subject to } \;\;& c_i(x) \leq 0, \; i = 1, \ldots, m \\ & h_j(x) = 0, \; j = 1, \ldots, n \end{aligned} $$

Can be written more abstractly as:

$$ \operatorname*{minimize}_{x \in S} \; f(x) $$

Why Optimization?

Optimization is used as a primary computational tool in many fields: