cos (4x°+120°)-cos (4x°+20°)= -2 sin 50
Matematika
muhammadputra2
Pertanyaan
cos (4x°+120°)-cos (4x°+20°)= -2 sin 50
1 Jawaban
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1. Jawaban zahrazahwa
cos(4x+120)-cos(4x+20)= -2.sin 1/2(jumlah).sin1/2(selisih)
-2.sin(4x+70).sin50= -2.sin 50
sin (4x+70) = 1
sin (4x+70)=sin 90
4x + 70=90
4x. = 20
x = 5