Question

If A is equal to 30 degree verify cos 2A = 2 cos square A -1

Answer 1

Step-by-step explanation:

We are given that,

A = 30°

also,

2A = 30 × 2 = 60°

Cos30° = (√3)/2

Cos60° = 1/2

Now, we know that,

Cos2A = 2Cos²A - 1

Putting in the values,

LHS = Cos(60°) = 1/2

RHS = 2 × (Cos(30°))² - 1

= 2 × (√3/2)² - 1

= 2(3/4) - 1

= 3/2 - 1

= (3/2) - (2/2)

= (3 - 2)/2

= 1/2

Thus,

LHS = RHS

Hence, Verified.

Hope it helped and you understood it........All the best