On a certain mountain, the elevation z above a point (x,y) in a horizontal xy-plane at sea level is z=300-0.05x^2-0.02y^2....

On a certain mountain, the elevation 2 above a point (x, y) in a horizontal xyplane at sea level is z = 3000 0.05x2 0.02y2 feet. The positive x-axis points east, and the positive y-axis point north. A climber is at the point (100, 200, 1700). If the climber uses a compass reading to walk southeast, will he ascend or descend? At what rate