Решите уавнение 2cos x/2+1=0
2cos(x/2)=-1 Cos(x/2)=-1/2 x/2=±Π/3+2Πk x=±2Π/3 + 4Πk
1)2cos(x/2)=-1; 2)cos(x/2)=-1/2; 3)x/2=±Π/3+2Πk; 4)x=±2Π/3 + 4Πk.