Respuesta :

CastleRook
this is the concept of trigonometry, by trigonometric rules:
tan 2x=[2tan x]/[1-tan^2 x]
given that tan x=7/11
then:
tan 2x=[2*7/11]/[1-(7/11)^2]
=[14/11]/[1-49/121]
=[14/11]/[72/121]
=77/36