12. Use optimization to determine the dimensions of the rectangle of minimum perimeter among all rectangles of area 324 square feet. 13. Use L'Hopital's Rule to evaluate the following limit. _ 5x 3 sin x 11m .rU 9x 14' Use optimization to find positive numbers x and y satisfying the equation xy i 54 such that the sum 3): + 4}: is as small as possible. 2:: 15' Find the linear approximation LU) tox) = 7 cos x at a = ?. 16. Find H(x) such that H'(x) = 6x2 + 3 sec x tan x, with H(0) = 4. 17. Determine [3 sin 6 d6. 18. Determine the indefinite integral "+ [ ) ) dt. 19. Find all the antiderivatives of h(x) = 16x3 - 9x7. 20. Use L'Hopital's Rule to evaluate the following limit. 4 cos x - 4 lim x+0 5x2