cos 105 + cos 15 + sin30
Matematika
MuhammadAbduhh
Pertanyaan
cos 105 + cos 15 + sin30
1 Jawaban
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1. Jawaban nathanaelta35
cos 105 + cos 15 = 2 cos [tex] \frac{1}{2} [/tex] (a + b) . cos [tex] \frac{1}{2} [/tex] (a - b)
= 2 cos 60 . cos 45
= 2 [tex] \frac{1}{2} [/tex] . [tex] \frac{1}{2} \sqrt{2} [/tex]
= [tex] \frac{1}{2} \sqrt{2} [/tex]
cos 105 + cos 15 + sin 30
= [tex] \frac{1}{2} \sqrt{2} [/tex] + [tex] \frac{1}{2} [/tex]
= [tex] \frac{1}{2} [/tex] ([tex] \sqrt{2} + 1 [/tex])