===== Ángulo doble =====

==== sin 2x ====
  *<m 15>sin 2x ~=~  2 sin x . cos x</m>

==== cos 2x ====
  *<m 15>cos 2x ~=~  cos^2 x - sin^2 x</m>
  *<m 15>cos 2x ~=~  1 - 2 sin^2 x</m>
  *<m 15>cos 2x ~=~  2 cos^2 x - 1</m>

==== tan 2x ====
  *<m 15>tan 2x ~=~  { 2 tan x } / { 1 - tan^2 x }</m>

==== cot 2x ====
  *<m 15>cot 2x ~=~  { cot^2 x - 1 }/{2 cot x}</m>

===== Auxiliares =====

==== sec 2x ====
  * <m 15>sec 2x + 1 ~=~  { tan 2x } / { tan x }</m>
  * <m 15>sec 2x - 1 ~=~  tan 2x . tan x</m>

==== csc 2x ====
  * <m 15>2 csc 2x ~=~  cot x + tan x</m>

==== cot 2x ====
  * <m 15>2 cot 2x ~=~  cot x - tan x</m>

==== Formulas de Degradación ====

Se infiere de Cos 2x :

  * <m 15>2 sin^2 x = 1 - cos 2x</m>
  * <m 15>2 cos^2 x = 1 + cos 2x</m>