Tentukan nilai cos 75°+cos 15°
Jawaban Terkonfirmasi
Kelas 10 Matematika
Bab Trigonometri
cos 75° + cos 15°
= 2 . cos ((75° + 15°)/2) . cos ((75° – 15°)/2)
= 2 . cos 45° . cos 30°
= 2 . 1/2 √2 . 1/2 √3
= 1/2 √6
Cos 75 + cos 15 = 2 cos (90/2) cos (60/2)
= 2 cos 45 cos 30
= 2 x 1/2 √2 x 1/2 x √3
= (1/2)√6