Fórmulas de “Trigonometría Áurea” para las funciones Seno y Coseno

In this paper, a new mathematical constant is defined (we called it β), whose properties along with the golden number’s properties, allow us to obtain very simple algebraic expressions for the trigonometric functions sine and cosine evaluated in different angles. We obtained a simple expression for the area of a regular pentagon inscribed within a circle with radio 1. The calculations of the formulas giving us the value of the trigonometric functions, expressed as a function of the constants φ and β, are summarized in two tables at the end of this paper. The tables were created following an analogous procedure as the one used by the astronomer Ptolemy, to find the numerical values of his famous table of chords, documented in the first book of his great work The Almagest.