Jawapan:
# x = pi / 3 + 2kpi #
# x = -pi / 3 + 2kpi #
Penjelasan:
# 2cos ^ 2x + 3cos-2 = 0 #
#sqrt (Δ) = sqrt (25) = 5 #
# t_1 = (- 3-5) / 4 = -2 #
# t_2 = (- 3 + 5) / 4 = 1/2 #
# cosx = 1/2 #
# x = pi / 3 + 2kpi #
# x = -pi / 3 + 2kpi #
k adalah sebenar