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