2. Suppose that r, ex are positive numbers, E is a convex subset of Rn such that E c Br(O), and there exists a sequence Xk E E such that Xk ---t 0 as k ---t 00. If f: Br(O) ---t R continuously differentiable and If(x)1 ::; Ilxll'" for all x E E, prove that there is an M > 0 such that If(x)1 ::; Mllxll for x E E.