If y = x + tan x, ⇒ tan x = y-x…. (i) Differentiating with respect to x Differentiating with respect to x ⇒ ⇒ ⇒ ⇒ ⇒ 
[putting value of tan x from (i) ]
1
If y = x + tan x, ⇒ tan x = y-x…. (i) Differentiating with respect to x Differentiating with respect to x ⇒ ⇒ ⇒ ⇒ ⇒ [putting value of tan x from (i) ]