Question

Хелп plz: sin82°30'*sin37°30'
Cos35°sin25°
Cos15°cos5°

Answer 1

sin82°30'*sin37°30' = 0.5(cos45-cos120)= 0.5(√2/2 + 0.5)=$frac{ sqrt{2} + 1 }{4}$
Cos35°sin25° = 0.5(sin60 + sin 10)=0.5(√3/2 - sin 10)
Cos15°cos5° = 0.5(cos20 + cos10)

Answer 2

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