kak abang, bantu jawab dong.. no 20. makasih sebelumnya

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3sin² x + sin x - 2 = 0
(3sin x - 2)(sin x + 1) = 0
sin x = 2/3 ---> x = 41,8° dan 138,2°
sin x = -1 --> x = 270°

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4sin² x + 7cos x - 7 = 0
4(1 - cos² x) + 7cos x - 7 = 0
(-4cosx + 3)(cosx - 1) = 0
cos x = -3/4 --> x = -138,6° dan 221,4°
cos x = 1 --> x = 0° dan 360°
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2 sin x = tan x
2 = 1/cos x
cos x = 1/2
x = 60° dan 300°

Banyak amat ya :)

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cos (x + 60) = sin x
x + 60 = 90 - x
2x = 90 - 60
x = 15°