Question

If A=30 verify that
Cos 2A = 1-2 sin 2 A

Answer 1

Answer:

Step-by-step explanation:

Actually it should be 1-sin²A.

Cos²A=cos²30

Cos²30=(root3/2)²

Cos²30=3/4

Now, 1-sin²A=1-sin²30

Sin²30=1/2*1/2

Sin²30=1/4

Therefore, 1-sin²30=1-1/4

=3/4=LHS

Therefore, cos²A=1-sin²A