2sin2x+1=0

Answer 1

sin2x = -1/2
2x = 210° or 330°
x = 105° or 165°
the period of sin2x is 180°, so two other answers are
105+180 = 285° or 165+180 = 345°

in degrees: x = 105° 165° 285° 345°
in radians: x = 7π/12, 11π/12,19π/12, 23π/12