# Maximizing an Objective

All solvers attempt to minimize an objective function. If you have a maximization problem, that is, a problem of the form

$\underset{x}{\mathrm{max}}f\left(x\right)$,

then define and minimize $g$.

For example, to find the maximum of $\mathrm{tan}\left(\mathrm{cos}\left(x\right)\right)$ near , evaluate

[x,fval] = fminunc(@(x)-tan(cos(x)),5)
Local minimum found.

Optimization completed because the size of the gradient is less than
the value of the optimality tolerance.
x = 6.2832
fval = -1.5574

The maximum is 1.5574 (the negative of the reported fval), and occurs at x = 6.2832. This answer is correct because, to five digits, the maximum is , which occurs at .