Question

3 tan ^2A-1 =0.A is an acute angle find cos 2A

Answer 1

Answer:

Step-by-step explanation:

Given that,

3 tan²A - 1 =0

3 tan²A = 1

   tan²A = $\frac{1}{3}$

   tanA = $\frac{1}{\sqrt{3}}$

   A = 30°

now,

Cos2A

           = cos 2 x 30

          = cos 60°

          = $\frac{1}{2}$