Tentukan HP dari: sin (3x + Π/3) + sin (3x - Π/3) = -3/2

[tex](sin3x.cos60+cos3x.sin60)+(sin3x.cos60-cos3x.sin60)= \frac{-3}{2} \\\\ 2sin3xcos60 = \frac{-3}{2} \\\\ sin3x = \frac{-3}{2} \\\\ 3x=arcsin( \frac{-3}{2}) \\\\ x = \frac{arcsin( \frac{-3}{2}) }{3} [/tex]