f(x)=2sin(x+пи/3)+1
f(x)=0
2sin(x+пи/3)+1 = 0
sin(x+пи/3) = -1/2
x+pi/3 = -pi/6 + 2pik
x = -pi/6-pi/3 + 2pik
x = -pi/2 + 2pik
x+pi/3=7pi/6+2pik
x= 7pi/6 -pi/3 +2pik
x=5pi/6+2pik
