Define what it means for a function f to be continuous at x = a. (b) [2 points] If a function f is continuous at x = a, must f be differentiable there too? If "yes", give a brief argument why, otherwise, give an example that fails. (c) [3 points] Let( ) cos 1 sin 2 ( ) 2 2 x x x x f x x Is f continuous at2 x ?