52. Find the point on the hyperbola xy = 8 that is closest to the point (3, 0). 55. In A ABC, D lies on AB, CD I AB, AD = BD = 4 cm, and CD | = 5 cm. Where should a point P be chosen on CD so that the sum PA | + |PB | + | PC | is a minimum? 56. Solve Exercise 55 when |CD = 2 cm. 58. A metal storage tank with volume V is to be constructed in the shape of a right circular cylinder surmounted by a hemi- sphere. What dimensions will require the least amount of metal