tanx = 2/5 then tanx = ? Solution We\'ll write tan 2x as a sum of 2 angles. tan 2x = tan(x+x) tan 2x = (tan x+ tan x)/[1-(tanx)^2] tan 2x=2tan x/[1-(tanx)^2] We know, from enunciation, that tan x= 2/5. We\'ll substitute the value of tan x in the formula for tan 2x. tan 2x = 2*2/5/(1 - 4/25) tan 2x = (4/5)*(25/21) We\'ll simplify: tan 2x = 4*5/21 tan 2x = 20/21.

1. tanx = 2/5 then tanx = ?
Solution
We'll write tan 2x as a sum of 2 angles.
tan 2x = tan(x+x)
tan 2x = (tan x+ tan x)/[1-(tanx)^2]
tan 2x=2tan x/[1-(tanx)^2]
We know, from enunciation, that tan x= 2/5.
We'll substitute the value of tan x in the formula for tan 2x.
tan 2x = 2*2/5/(1 - 4/25)
tan 2x = (4/5)*(25/21)
We'll simplify:
tan 2x = 4*5/21
tan 2x = 20/21