Question

if cos2A=1/2, find the value of A?

Answer 1

Answer:

A = 30°

Step-by-step explanation:

Given: cos2A = 1/2

⇒ cos 2A = cos 60

⇒ 2A = 60

⇒ A = 30°

Therefore, the value of A = 30°

Hope it helps!

Answer 2

Answer: 30⁰

Step-by-step explanation:

Given : cos 2A = $\frac{1}{2}$

Solution : cos 2A = $\frac{1}{2}$

               ⇒ 2A = cos ⁻¹ ( $\frac{1}{2}$ )

               ⇒  2A = 60⁰

               ⇒ A = $\frac{60}{2} = 30⁰$

Verification : LHL = cos 2A

                             = cos ( 2 * 30⁰)

                             = cos ( 60⁰)

                             = $\frac{1}{2}$

                             = RHL

Therefore , A = 30⁰.

Hope you find it useful.

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