Решить тригонометрическое уравнение. sin x + cos x/2 = 0 !

Sin(x/2)+cosx=1 
sin(x/2)+cos²(x/2)-sin²(x/2)=cos²(x/2)+sin²(x/2) 
sin(x/2)-2sin²(x/2)=0 
sin(x/2)•(1-2sin(x/2))=0 
1)sin(x/2)=0 => x/2=kπ => x=2kπ, k ε Z; 
2)sin(x/2)=½ => x/2=(-1)^k•π/6+kπ => x=(-1)^k•π/3+2kπ, k ε Z.

2 sin Х/2 * cos Х/2 + cos Х/2 = 0

cos Х/2 ( 2 sin Х/2 + 1 ) = 0

1) cos Х/2 = 0                     2) 2 sin Х/2 + 1 = 0    ответ: Х=П+2Пп,  

                                                                              Х = ( - 1)к( - П/3) + 4 Пк                               

Х/2 = П/2 + Пп                     sin Х/2 = - 1/2

Х=П + 2 Пп                           Х/2 Х= ( - 1)к( - П/6) + 2 Пк

                                              Х = ( - 1)к( - П/3) + 4 Пк, к∈z