3. * Pick 2 of the following problems to solve by hand (a) Find the shortest distance from the point (4,2, 0) to the cone z' = x- + y- (b) Find the dimensions of the rectangular box with largest volume if the total surface area is given as 64cm- (c) Use Lagrange Multipliers, find max and min : f(x, y) = y- - x-; +y =1 (d) Use Lagrange Multipliers, find max and min :: f(x, y, z) = yz+xy; xy =1, y-+ Z- = 1