Far East Journal of Mathematical Education

The Far East Journal of Mathematical Education is a peer-reviewed journal focused on mathematical education. It publishes research papers that enhance understanding of mathematical concepts and encourages the use of technology, statistics, algorithms, and simulations in mathematics learning.

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PICTORIAL PROOF OF TANGENT DIFFERENCE IDENTITY

Authors

  • Long Wang

Keywords:

tangent difference identity

DOI:

https://doi.org/10.17654/0973563126001

Abstract

In this paper, we give a pictorial proof of tangent difference identity.

Received: September 21, 2025
Accepted: October 16, 2025

References

[1] R. Nelsen, Proofs Without Words, MAA, Washington DC, 1993, pp. 34-35.

[2] Y. Kobayashi, Proofs without words: tangent double angle identity, College Math. J. 44 (2013), 47.

[3] L. Wang, Proofs without words: sine sum identity, College Math. J. 45 (2014), 190.

[4] L. Wang, Proofs without words: cosine difference identity, College Math. J. 45 (2014), 370.

[5] L. Wang, Proofs without words: sine difference identity, Far East Journal of Mathematical Education 26(2) (2024), 123-124.

[6] L. Wang, Proofs without words: tangent sum Identity, Far East Journal of Mathematical Education 27(1) (2025), 61-62.

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Published

27-11-2025

Issue

Vol. 28 No. 1 (2026)

Section

Articles

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How to Cite

PICTORIAL PROOF OF TANGENT DIFFERENCE IDENTITY. (2025). Far East Journal of Mathematical Education, 28(1), 1-2. https://doi.org/10.17654/0973563126001