Question

Nilai Dari sin 15°+cos 105°–2sin 37°+cos 60°+2 cos 53° adalah

Answer 1

Sin 15=sin(45-30)
=sin 45.cos 30 - cos 45. sin 30
= 1/4 √6 - 1/4 √2

cos 105 = cos (60+45)
=cos 60.cos 45 + sin 60. sin 45
=1/4 √2 + 1/4 √6

hasil = 1/4 √6 - 1/4 √2 + 1/4 √2 + 1/4 √6 - 2.(3/5) + 1/2 + 2. (3/5)
= 1/2 √6 + 1/2
= 1/2 (√6 + 1)