a piece of rectangular sheet metal is 20 in wide. It's to be made into rain gutter by turning the edges to form parallel sides. Let x represent the length of each of parallel sides.
a. give restrictions on x.
b. determine a function of A that gives the area of a cross section of the gutter.
c. for what values of x will A be a max (and thus maximize the amount of water that gutter will hold?
d. what is max area?
e. for what values of x will the area of a cross section be less than 40 square in?