Question

Find an exact value cos 75°

Answer 1

Answer:

0.2588

Step-by-step explanation:

Answer 2

Answer:

(√3 - 1) / 2√2.

Step-by-step explanation:

Using the compound angle identity

cos(A + B) = cosA cosB - sinA sinB:-

cos 75

= cos (45 + 30)

= cos 45 cos 30 - sin 45 sin 30

= 1 / √2 * √3/2 - 1 / √2 *  1 / 2

= √3 / 2√2 - 1 / 2√2

= (√3 - 1) / 2√2.