1-cosx=2*sin(x\2) 2sin²(x/2)-2sin(x/2)=0 sin(x/2)(sin(x/2)-1)=0 a) sin(x/2)=0 x/2=πn x1=2πn б) sin(x/2)-1=0 sin(x/2)=1 x/2=π/2+2πn x2=πn+4πn