Q10 (7 points) (a) [4] Use the definition of derivative to determine whether f(:1:) 2 [ml cos a: is differentiable at a: = 0. (b) [3] Suppose that a function g is odd so thatg(a3) = g(:1:), and suppose lim 9(3) 2 L. :c>0+ For which values of L may 9(32) be differentiable at a: = 0? Explain clearly using concepts from the course. (An answer with no justification is worth zero marks.)