Question Number 10114 by JAZAR last updated on 24/Jan/17

how can demontred  tan 3x=_(         ) ((3tanx−tan^3 x)/(1_ −3tan^2 x))  pleace help me

Answered by mrW1 last updated on 24/Jan/17

tan 3x=tan (x+2x)  =((tan x+tan 2x)/(1−tan x tan 2x))  =((tan x+((2tan x)/(1−tan^2  x)))/(1−tan x×((2tan x)/(1−tan^2  x))))  =((tan x (1−tan^2  x)+2tan x)/(1−tan^2  x−2tan^2  x))   =((3tan x−tan^3  x)/(1−3tan^2  x))