Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2012/ia/paper-1/11d/i/solution

Fix and put , . Then . The bounded monotone sequence theorem gives a limit . If , it lies in the domain, where continuity allows passage to the limit in the recurrence: . That is a fixed point, contrary to . Hence . Continuity is used at a possible positive limiting point, not at the excluded endpoint zero.

New to topics? Read the docs here!