Using the formula tan 2θ = ,obtain the value of tan 15°.

⇒ 1/√3 =

⇒ 1 – tan ² 15° = 2√3(tan 15°)

⇒ tan ² 15° + 2√3(tan 15°) – 1= 0

⇒ tan 15 ° =

Since, tan 15° is positive as it is lying in first quadrant, and -√3 – 2<0, therefore it can’t be the value of tan 15°.

∴ tan 15 ° = 2 - √ 3.