50 . решите,. =) 1.решите уравнение: а)cost=√2/2 б)cos(3π+t)=-1/2

Решение
1)  cost = √2/2
 t = (+ -)arccos(√2/2) + 2πk, k∈z
t = (+ -)(π/4) + 2πk, k∈Z

2) cos(3π + t) = - 1/2
- cost = - 1/2
cost = 1/2
 t = (+ -)arccos(1/2) + 2πn, n∈z
t = (+ -)(π/3) + 2πn, n∈Z