Question

if theta is equal to 30 show that cos 2 theta is equal to 2 cos squared theta minus one ​

Answer 1

Answer:

Ayush here..

Given:- Φ =30°.

A/Q,

Cos2Φ = 2Cos²Φ - 1

Cos2×30° = 2Cos²30 - 1

Cos60° = 2×(√3/2)² - 1

1/2 = 2 × 3/4 - 1

1/2 = 3/2 - 1

1/2 = 3 - 2/2

1/2 = 1/2..

Hence,proved..

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