cos 105 dikali cos 45
Matematika
arifah2724
Pertanyaan
cos 105 dikali cos 45
1 Jawaban
-
1. Jawaban Anonyme
Kelas 10 Matematika
Bab Trigonometri
cos 105° = cos (60° + 45°)
cos 105° = cos 60° . cos 45° - sin 60° . sin 45°
cos 105° = 1/2 . 1/2√2 - 1/2 √3 . 1/2√2
cos 105° = 1/4 (√2 - √6)
cos 105° . cos 45°
= 1/4 (√2 - √6) . 1/2 √2
= 1/8 . (√2² - √12)
= 1/8 . (2 - 2√3)
= 1/4 (1 - √3)