Question

Подробно пожалуйста
arccos (cos 4п\3)

Answer 1

arccos(cosx)=x,x∈[0;π]
cos4π/3=cos(π+π/3)=-cosππ/3
arccos (cos 4п\3)=arccos(-cosπ/3)=π-arccos(cosπ/3)=π-π/3=2π/3