L Let n be an integer, n > 1. Consider the function g defined by ( acy 2 ) n g(x, y) = 2 2 + 2/2 , if (x, y) + (0,0) ; 0 , if (x, y) = (0,0) . (a) [ | mark -) Using the principal definition of partial derivatives, show that 09 (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