# Aptitude | Trigonometry & Height and Distances | Question 3

If tan (x+y) tan (x-y) = 1, then find tan (2x/3)?**(A)** 2/√3**(B)** 1/2**(C)** 1/√2**(D)** 1/√3**Answer:** **(D)****Explanation:** tanA = cotB,

tanA*tan B = 1

So, A +B = 90^{o}

(x+y)+(x-y) = 90^{o}, 2x = 90^{o} , x = 45^{o}

Tan (2x/3) = tan 30^{o} = 1/√3

Quiz of this Question

Please comment below if you find anything wrong in the above post