Solve a maximum or minimum problem by differentiation
The sum of two non-negative lengths is \(22\,\mathrm{cm}\). Use their product as the quantity to be maximised
Let \(w\) be the first length and \(l\) the second length
\[w+l=22\]
\[A(w,l)=wl\]
The practical domain is \(w\in\left[0,22\right]\)
Use differentiation to find the requested optimum