cos 105° x cos 15 bantuannya
Matematika
MarikoSendy
Pertanyaan
cos 105° x cos 15
bantuannya
bantuannya
1 Jawaban
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1. Jawaban insanii1
= 1/2 (2 cos 105 cos 15)
= 1/2 (cos (105+15) + cos (105-15))
= 1/2 (cos (120+90))
= 1/2 ( -1/2 + 0 )
= -1/4