Sharol Nau

A classical calculus problem, the so-called Paper Creasing Problem, deals with extremizing the length of the crease formed when a rectangular sheet of paper is altered by folding one corner, say the lower right-hand corner, to the opposite edge. The length of the crease depends on the distance the active corner is from the upper left-hand corner. Using this distance as the variable, the problem naturally divides into several sub-domains, in which the maximizing and minimizing points may occur at interior or endpoints depending upon the dimensions of the sheet.