В)
cos t = -1/2
t = ±arccos(-1/2)+2πn, n∈Z
t = ±(π-arccos 1/2)+2πn, n∈Z
t = ±(π-π/3) + 2πn, n∈Z
t = ± 2π/3 + 2πn, n∈Z - ответ
Г)
sin t = √2/2
t = arcsin √2/2 + 2πn, n∈Z
t = π-arcsin √2/2 + 2πn, n∈Z
t = π/4 + 2πn, n∈Z
t = π - π/4 + 2πn, n∈Z
t = 3π/4 + 2πn, n∈Z - ответ
В)
cos t = -1/2
t = ±arccos(-1/2)+2πn, n∈Z
t = ±(π-arccos 1/2)+2πn, n∈Z
t = ±(π-π/3) + 2πn, n∈Z
t = ± 2π/3 + 2πn, n∈Z - ответ
Г)
sin t = √2/2
t = arcsin √2/2 + 2πn, n∈Z
t = π-arcsin √2/2 + 2πn, n∈Z
t = π/4 + 2πn, n∈Z
t = π - π/4 + 2πn, n∈Z
t = π/4 + 2πn, n∈Z
t = 3π/4 + 2πn, n∈Z - ответ