Editing Hyperbolic triangle (section)

====Equilateral triangle====
The trigonometry formulas of right triangles also give the relations between the sides ''s'' and the angles ''A'' of an [[equilateral triangle]] (a triangle where all sides have the same length and all angles are equal).

The relations are:

:<math>\cos A= \frac{\textrm{tanh}(\frac12 s) }{\textrm{tanh} (s)}</math>

:<math>\cosh( \frac12 s)= \frac{\cos(\frac12 A)}{\sin( A)}= \frac{1}{2 \sin(\frac12 A)}</math>