A Limit Hidden in a Recurrence

Problem

A sequence has a1=1a_1 = 1 and

an+1=an+12an.a_{n+1} = a_n + \frac{1}{2a_n}.

Evaluate

limn(ann).\lim_{n \to \infty}\left(a_n - \sqrt{n}\right).

Answer

Solution

Difficulty8/10
TopicsLimits, calculus, sequences, Estimation, Telescoping

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