An Elementary Proof on the Limit Superior and Limit Inferior of cos(n) and sin(n)

We present an elementary proof of lim sup n cos(n) = lim sup n sin(n) = 1, and lim inf n cos(n) = lim inf n sin(n) = -1.Our approach avoids the use of the Kronecker density theorem, equidistribution theorem, or any concepts from Diophantine approximations, providing a more direct and accessible argument.

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Publication Details

Journal
Global Journal of Pure and Applied Mathematics
Published
2025-03-20
DOI
https://doi.org/10.37622/gjpam/21.1.2025.75-80
Primary Topic
Inertial Sensor and Navigation
Type
article
Field-Weighted Citation Impact
0.00
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article

An Elementary Proof on the Limit Superior and Limit Inferior of cos(n) and sin(n)

Quansheng Wu
Global Journal of Pure and Applied Mathematics
Inertial Sensor and Navigation
article

An Elementary Proof on the Limit Superior and Limit Inferior of cos(n) and sin(n)

Quansheng Wu
article en

Abstract

We present an elementary proof of lim sup n cos(n) = lim sup n sin(n) = 1, and lim inf n cos(n) = lim inf n sin(n) = -1.Our approach avoids the use of the Kronecker density theorem, equidistribution theorem, or any concepts from Diophantine approximations, providing a more direct and accessible argument.

Global Journal of Pure and Applied MathematicsVol. 21(1)
West Texas A&M University (US)
Openalex Percentile: Top 88%
Inertial Sensor and Navigation
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An Elementary Proof on the Limit Superior and Limit Inferior of cos(n) and sin(n) — Quansheng Wu · Global Journal of Pure and Applied Mathematics (2025) | TGRS Research Map | TGRS