Could you please help me with these questions?

8. A farmer Wishes to fence off a rectangular pasture along a straight river, the side along the river requiring no fence. He has Wire to fence a distance of 800 meters. What is the area of the largest pasture of the above description that can be fenced? 9. Let f(x) = (1 + 3:2)'%. (a) Show that (1 + m2)f'(:r) + 22f(:r) = 0. (b) Let n be a non-negative integer, show that (1 + x2)f("+2)(:c) + (2n + 3):cf("+1)(:r) + (n + 1)2f(")(:r) : 0. (c) Hence, or otherwise, nd the Taylor series of (1 + 332) i at :1: = 0 up to the term 13\