Question

The perimeter of a rectangle is 20 feet. of all possible dimensions, the maximum area is 25 square feet when its length and width are both 5 feet. are there dimensions that yield a minimum area? explain.

Answer 1

You will get a very small area if you increase the length  until it is just short of 10 feet
But when it is 10 feet you no longer have a rectangle! Just a straight line with area zero! So there is no real minimum area.

So there is no real minimum value