1.(15%) Find the local maximum and minimum values and saddle points of the function f(x,y)=ey(y2-x2).

2.(10%) The length width w, and height h of a box change with time. At a certain instant the dimensions are= Im and w= h= 2 m, and t and ware increasing at a rate of 2 m/s while h is decreasing at a rate of 3 m/s. At that instant find the rates at which the length of a diagonal are changing. (The length of diagonal .)