Question

Подробно пожалуйста
arccos (cos 4п\4)

Answer 1

arccos(cosx)=x,x∈[0;π]

cos4π/4=cos(π+π/4)=-cosππ/4

arccos (cos 4п\4)=arccos(-cosπ/4)=π-arccos(cosπ/4)=π-π/4=3π/4