Past exam of the mathematics course of the University of Cambridge 2017 ib Paper 1 11G iii Solution Created 2026-09-24 Updated 2026-10-05
True. Define and . The map is Lipschitz continuous with constant one. The restriction of to is uniformly continuous by the Heine-Cantor theorem; its modulus of continuity combined with proves uniform continuity of on all of . For each fixed , once we have . HenceThis pointwise approximation by uniformly continuous functions even gives eventual equality on every fixed bounded interval. It need not give uniform convergence on the whole line, as the bounded counterexample in part (i) already demonstrates.