Question

if A = 30 , verify that cos 2A = 1 - tan ^2 A / 1 + tan^2 A

Answer 1

Answer:

In the attachment.. Hope it's helpful..

Answer 2

Answer:

Step-by-step explanation:

A=30

Hence,cos2A=1-tan²A/1+tan²30

cos2(30)=1-tan²30/1+tan²30

cos60=1-(1/√3)²/1+(1/√3)²

1/2=1-1/3÷1+1/3

1/2=3-1/3÷3+1/3

On RHS 2 will be divided,

1/2=2/4

1/2=1/2

Hence,cos2A=1-tan²A/1+tan²A