Question

(1-tan^2 30°)/(1+tan^2 30°)=

Answer 1

tan 30 = 1/root3
squaring on both sides
tan^2 30 = 1/3
now,
1- tan^2 30/ 1+ tan ^2 30
=1- (1/3) / 1+ (1/3)
=(3-1/3)/(3+1/3)
=2/3*3/4
=2/4
=1/2

Answer 2

Step-by-step explanation:

formula, cos2A=(1-tan^2A)/(1+tan^2A)

putting A=30°

cos2(30°)=cos60°

= 1/2