directional derivitive

The depth of a pond at the point with coordinates(x,y) is given by $h(x,y) = 2x^2 + 3y^2$ 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?
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