Trigonometric Ratios Can Prove the Pythagorean Theorem

Fuente: arXiv
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Autori principali: Kise, Shoya, Uehara, Takesa, Shinzato, Takashi
Natura: Preprint
Pubblicazione: 2025
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_version_ 1866910992959537152
author Kise, Shoya
Uehara, Takesa
Shinzato, Takashi
author_facet Kise, Shoya
Uehara, Takesa
Shinzato, Takashi
contents Recent interest in noncircular trigonometric proofs has underscored the need for alternative methodologies. Jackson and Johnson's 2024 study addresses a longstanding gap in the foundations of trigonometric proofs. Inspired by the work of Jackson and Johnson [JJ24], we present three noncircular proofs of the Pythagorean theorem based on trigonometric identities. First, we establish the Pythagorean theorem via an isosceles triangle construction and the tangent double-angle formula. Second, we present an alternative proof utilizing an isosceles-triangle and the angle-bisector theorem. Third, we derive a novel trigonometric relation from the angle-bisector theorem, thereby unifying and extending the two preceding approaches. These approaches collectively demonstrate that the principal contribution of Jackson and Johnson lies in their strategic use of the double-angle formula. These proofs clarify the role of trigonometric identities independent of infinite series.
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publishDate 2025
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spellingShingle Trigonometric Ratios Can Prove the Pythagorean Theorem
Kise, Shoya
Uehara, Takesa
Shinzato, Takashi
History and Overview
Algebraic Geometry
Recent interest in noncircular trigonometric proofs has underscored the need for alternative methodologies. Jackson and Johnson's 2024 study addresses a longstanding gap in the foundations of trigonometric proofs. Inspired by the work of Jackson and Johnson [JJ24], we present three noncircular proofs of the Pythagorean theorem based on trigonometric identities. First, we establish the Pythagorean theorem via an isosceles triangle construction and the tangent double-angle formula. Second, we present an alternative proof utilizing an isosceles-triangle and the angle-bisector theorem. Third, we derive a novel trigonometric relation from the angle-bisector theorem, thereby unifying and extending the two preceding approaches. These approaches collectively demonstrate that the principal contribution of Jackson and Johnson lies in their strategic use of the double-angle formula. These proofs clarify the role of trigonometric identities independent of infinite series.
title Trigonometric Ratios Can Prove the Pythagorean Theorem
topic History and Overview
Algebraic Geometry
url https://arxiv.org/abs/2506.06304