Question

kuis

Nilai dari sin 15°(cos 105° – sin 75°) = .....​

jawaban pertama = beA
jawaban benar = beA​

Answer 1

Dengan
sin(a+b) = sin(a)cos(b) + sin(b)cos(a)
sin(a-b) = sin(a)cos(b) - sin(b)cos(a)
cos(a+b) = cos(a)cos(b) - sin(a)sin(b)
cos(a-b) = cos(a)cos(b) + sin(a)sin(b)
maka hasil dari
sin 15°(cos 105° – sin 75°) =
sin (45°-30°)(cos(45°+60°) – sin(45°+30°)) =
(sin45cos30-sin30cos45)(cos45cos60-sin45sin60 - (sin45cos30+sin30cos45)) =
(½√2(½√3)-½(½√2))(½√2(½)-½√2(½√3)-[½√2(½√3)+½(½√2)]) =
(¼√6 - ¼√2)(¼√2-¼√6 - (¼√6+¼√2)) =
(¼√6 - ¼√2)(¼√2-¼√6 - ¼√6-¼√2) =
(¼√6 - ¼√2)(- ½√6) =
-⅛(6) + ⅛√12 =
-¾ + ⅛√4√3 =
-¾ + ⅛(2√3) =
¼√3 - ¾ =

Answer 2

semogq bermanfaat........