Решите уравнения a) sin(2x-)=- б) cos(=

А)2х-π/4=(-1)^n+1)π/4+πn.  n∈z
2x=(-1)^(n+1)π/4+π/4+πn
x=(-1)^(n+1)π/8+π/8+πn/2
x1=-π/8+π/8+πr.   r-четное
x2=π/8+π/8+πk+π/2=3π/4+πk     ..k-нечетное число
б)х/3+π/6=+,-π/3+2πn.  n∈z
x/3=+/-π3-π/6+2πn
x=+/-π-π/2+6πn
x1=π-π/2+6πn=π/2+6πn  n∈Z
x2=-π-π/2+6πn=-3π/2+6πk   k∈z