Cos t = -1/2 cos t = √2/2

Question

Cos t = -1/2
cos t = √2/2

Answer 1

Arccos(-1/2)=П-arccos(-1/2)=П-П/3=2/3П
t=2/3П=120 градусов
arccos√2/2=П/4
t=П/4=45 градусов.