А) 2cosx+1=0
2cosx=-1
cosx=-1/2
x=+-arcos a+2kπ, k∈Z
x=+- 2π/3+2kπ
б) tg2x+1=0
tg2x=-1
2x=-π/4+2kπ
x=-π/8+kπ
в)sin(x/3+π/4)=-1
x/3+π/4=-π/2+2kπ
x/3=-π/2+π/4+2kπ
x/3=-π/4+2kπ
x=-3π/4+6kπ
(2^2-1)(2^2+1)=2^4-1
(2^4-1)(2^4+1)=2^8-1
(2^8-1)(2^8+1)=2^16-1
(2^16+1)(2^16-1)=2^32-1
(2^32-1)(2^32+1)=2^64-1
1) 1, 2, 3, 6, 9, 18.
2) 1, 2, 4.
3) 1, 2, 5, 10