Exercise 1225Algebra › Equations and radicalsOlympiadAdded 4 Nov 2026
The integer part of a telescoping sum
#recurrence#telescoping#floor#monotone sequence
Statement
Define and . Compute
Hint
From , express as a difference of two consecutive terms .
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Solution
Telescoping. Since ,
Hence
Size of . The sequence is positive and increasing (). Moreover and . So , hence .
Conclusion. The sum lies in , so its integer part is .
Check. With only terms the sum is .
Lesson. When a recurrence has the form , the quantity telescopes.