Question

Cos 75 + sin 45 brp?

Answer 1

Cos 75 = cos(45 + 30) = cos 45 . cos 30 - sin 45 . sin 30
= 1/2 √2 . 1/2 √3 - 1/2 √2 . 1/2
= 1/4 √6 - 1/4 √2
= (√6 - √2) / 4
sin 45 = 1/2 √2
maka cos 75 + sin 45 = (√6 - √2) / 4 + √2 / 2
= (√6 - √2 + 2√2) / 4
= (√6 + √2) / 4
=