回答:
#S = {pi / 6 + 2pin,(5pi)/ 6 + 2pin,x = pi / 2 + 2pin}#
说明:
使用Double Argument属性:
#cos2A = 1-2sin ^ 2A#
#1-2sin ^ 2×+ 3sinx-2 = 0#
#2sin ^ 2X-3sinx + 1 = 0#
#(2sinx-1)(sinx的-1)= 0#
#2sinx-1 = 0或sinx-1 = 0#
#sinx = 1/2或sinx = 1#
#x = sin ^ -1(1/2)或x = sin ^ -1 1#
#x = pi / 6 + 2pin,(5pi)/ 6 + 2pin或x = pi / 2 + 2pin#
#S = {pi / 6 + 2pin,(5pi)/ 6 + 2pin,x = pi / 2 + 2pin}#