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Hofstadter Point


The Hofstadter point of a triangle DeltaABC is the perspector of its r-Hofstadter triangle and DeltaABC. The triangle center function is

 alpha=(sin(rA))/(sin(A-rA)).
(1)

The limiting Hofstadter point as r->0 has triangle center function

 alpha_(360)=A/a,
(2)

and is Kimberling center X_(360). The limiting Hofstadter point as r->1 has triangle center function

 alpha_(359)=a/A,
(3)

and is Kimberling center X_(359). These limits are taken in homogeneous trilinear coordinates. X_(359) and X_(360) are examples of transcendental triangle centers, since they have no trilinear coordinates or barycentric coordinates using only algebraic functions of the side lengths a, b, and c.


See also

Hofstadter Triangle

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References

Kimberling, C. "Hofstadter Points." Nieuw Arch. Wisk. 12, 109-114, 1994.Kimberling, C. "Major Centers of Triangles." Amer. Math. Monthly 104, 431-438, 1997.Kimberling, C. "Hofstadter Points." https://faculty.evansville.edu/ck6/tcenters/recent/hofstad.html.

Referenced on Wolfram|Alpha

Hofstadter Point

Cite this as:

Weisstein, Eric W. "Hofstadter Point." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/HofstadterPoint.html

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