cos (phi/12) - cos (5phi/12)
Matematika
erinayana
Pertanyaan
cos (phi/12) - cos (5phi/12)
1 Jawaban
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1. Jawaban Jkira
=> cos 15 - cos 75
=> cos (45-30) - cos (45+30)
=> (cos45cos30 + sin45sin30) - (cos45sin30 - sin 45cos30)
=> 2(sin45cos30)
=>2((1/2√2)(1/2√3))
=>1/2 √6