Climbing mountain, reaches a mountain that can be approximated by the function f (x, y) = x6 + 4x3 x2y y2 + 1, where the positive y direction is north and distances are in metres. a) someone begins at the point (0, 1), and walks south-east. Is he ascending or descending( express in dorection)? At what rate? b) When he climbs and reaches (1, 0), he decides to walk around the mountain for a while. What direction(s) could he walk in to remain at the same height? (Give your directions as a bearing rounded to the nearest degree - bearings are measured clockwise from north.)