Divine proportions: Rational trigonometry to universal geometry

2006 ◽  
Vol 28 (3) ◽  
pp. 73-74
Author(s):  
James Franklin
KoG ◽  
2020 ◽  
pp. 47-58
Author(s):  
William Beare ◽  
Norman Wildberger

We have another look at the Feuerbach theorem with a view to extending it in an oriented way to finite fields using the purely algebraic approach of rational trigonometry and universal geometry. Our approach starts with the tangent lines to three rational points on the unit circle, and all subsequent formulas involve the three parameters that define them. Tangency of incircles is treated in the oriented setting via a simplified form of cyclography. Some interesting features of the finite field case are discussed.


KoG ◽  
2017 ◽  
pp. 47-54
Author(s):  
Norman Wildberger

We extend rational trigonometry to higher dimensions by introducing rational invariants between $k$-subspaces of $n$-dimensional space to give an alternative to the canonical or principal angles studied by Jordan and many others, and their angular variants. We study in particular the cross, spread and det-cross of $2$-subspaces of four-dimensional space, and show that Pythagoras theorem, or the Diagonal Rule, has a natural generalization forsuch $2$-subspaces.


2003 ◽  
Vol 12 (09) ◽  
pp. 1743-1750 ◽  
Author(s):  
FRED C. ADAMS ◽  
MICHAEL T. BUSHA ◽  
AUGUST E. EVRARD ◽  
RISA H. WECHSLER

Astronomical observations strongly suggest that our universe is now accelerating and contains a substantial admixture of dark vacuum energy. Using numerical simulations to study this newly consolidated cosmological model (with a constant density of dark energy), we show that astronomical structures freeze out in the near future and that the density profiles of dark matter halos approach the same general form. Every dark matter halo grows asymptotically isolated and thereby becomes the center of its own island universe. Each of these isolated regions of space-time approaches a universal geometry and we calculate the corresponding form of the space-time metric.


2019 ◽  
Vol 2019 (2) ◽  
Author(s):  
Philip Candelas ◽  
Xenia de la Ossa ◽  
Jock McOrist ◽  
Roberto Sisca
Keyword(s):  

2013 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Denni Hariati Sinaga ◽  
Idha Sihwaningrum ◽  
Ari Wardayani

n this paper we discuss rational trigonometry in the field F17 ,in particular point, lines and their properties. A unique property in this field is given by the null lines.


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