Question

Cara mengerjakan
1. 2 sin6x cos3x
2. 2 cos 96˚ sin 21˚

Answer 1

1. 2 sin6x cos3x

2sin ( 2. 3x) . cos3x
2( 2 sin3x . cos 3x) .cos3x
4 sin3x cos² 3x


2. 2 cos 96˚ sin 21˚ = sin(96+21) = sin (96 -21)=sin 117 - sin 75


=

Answer 2

2 sinα cosβ = sin(α+β) + sin (α-β)

2 sin6x cos3x = sin(6x+3x) + sin(6x-3x)
= sin9x + sin3x

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2 cosα sinβ = sin(α+β) - sin (α-β)
2 cos96 sin21 = sin(96+21) - sin(96-21)
= sin117 - sin75
= 0,891 - 0,965
= -0,074