Question

sec A = 2 cos A is true for A = ______.

विकल्प

• 0°

• 30°

• 45°

• 60°

Answer 1

sec A = 2 cos A is true for A = 45°.

Explanation:

sec A = 2 cos A

`1/(cos A)` = 2 cos A

⇒ 1 = 2 cos²A

⇒ `1/2` = cos²A

⇒ cos A = `1/sqrt2`

= cos 45

A = 45°