How do you find the value of tan60 using the double angle identity?

1 Answer
Oct 18, 2017

sqrt3

Explanation:

Use trig identity:
tan 2a = (2tan a)/(1 - tan^2 a)
In this case:
tan (60) = (2tan (30))/( 1 - tan^2 30)
Trig table gives --> tan 30 = sqrt3/3 --> tan^2 30 = 3/9 = 1/3 -->
(1 - tan^2 30) = 1 - 1/3 = 2/3

tan (60) = ((2sqrt3)/3)(3/2) = sqrt3