Question

If tan 51 – 2 tan 12 = tan x and tan θ · tan(60 – θ) · tan(60 + θ) = tan x, then the minimum positive value of θ is equal to

(A) 9

(B) 13

(C) 17

(D) 21

Answer 1

Correct Answer is: (B) 13

We have

tan 51 – 2 tan 12 = tan (3θ) = tan (39) ⇒ = 13