Given: tan x = 3 cot x

⇒ tan x/cot x = 3

Since, cot x = 1/tan x

Therefore, tan x/cot x = 3 ⇒ tan² x = 3

Taking square root on both sides:

⇒ tan x = √3

⇒ tan x = tan 60°

Comparing both sides:

⇒ x = 60°