9.) A rectangular pen is built with one side against a barn. Two hundred meters of fencing are used for the other 3 sides of the pen. What is the maximum area of the pen?10.)A man wishes to get from an initial point on the corner of a square lake to the terminal point on the opposite corner of the lake (diagonally across). Each side to the lake is exactly 2 miles long. If he walks 4 mph and swims 2 mph what is the minimum time for the trip? Use L'Hopital's Rule to solve 11 and 12. 11.) lim *-x-1 x2 12.) lim x3 -3x2 +4 x-2 x4-4x3+7x2-12x+12