A sheet of paper for a poster is to be 18 ft^2 in area. The margins at the top and bottom are to be 9 in, and the margin at the sides 6 in. (i.) What is the area equation for the sheet of paper? (ii.) Using Calculus, determine what should be the dimensions of the sheet of paper for the poster to maximize the PRINTED area? Include the unit. Where applicable, approximate answer to 1 decimal place. (iii.) Use the Second Derivative Test to verify your answer found in (ii.).