2. For what values of a and b is the following equation true? kin(4x) b lim tat = 0. 3. Let f( ) = if I =0 1 if I = 0 (a) Show that f is continuous at 0. (Hint: Use the definition of continuity at a point.) (b) Show that / is not differentiable at 0. (Hint: Use the definition of differentiability at a point.)