Answer:
See below
Step-by-step explanation:
In the second step there should be (1 - cot x) instead of (1 + cot x)
(1 + tan x) [1 + cot(-x)]
= (1 + tan x) (1 - cot x)
= 1 - cot x + tan x - tan x cot x
= 1 - cot x + tan x - 1
= tan x - cot x
