Let n be an integer, n 2 1. Consider the function g defined by (acy? ) " g(x, y) = x2 + 2/2 , if (x, y) + (0, 0) ; 0 , if (x, y) = (0,0) . (a) [ | mark -] Using the principal definition of partial derivatives, show that (0, 0) = ay (0, 0) = 0. (b) [ [ mark ] Evaluate an appropriate limit to show that g is not differentiable at (0, 0) when n = 1. (c) [ [ mark ] Is g differentiable at (0,0) when n > 1? Justify your answer by evaluating the appropriate limit