pls help me to get startedQuote:

The depth of a pond at the point with coordinates(x,y) is given by feet.

a) If a boat at the point (-1,2) is sailing in the direction of 4i + j, is the water getting deeper or shallower? at what rate?

b) In which direction should the boat at (-1,2) move so that the water is getting deep fastest? At what rate?