Решите уравнения:

а) cos ( x/2 + π/4 ) + 1 = 0

б) 2cos π/6 * tgx * ctgx = 0

Решениеа) cos ( x/2 + π/4 ) + 1 = 0cos ( x/2 + π/4 )  = - 1x/2 + π/4 = π + 2πk, k∈Zx/2 = π - π/4 + 2πk, k∈Zx/2 = 3π/4 + 2πk, k∈Zx = 3π/2 + 4πk, k∈Zб) 2cos π/6 * tgx * ctgx = 02*(√3/2) * tgx * ctgx = 0 tgx * ctgx = 0tgx  = 0x = πn, n∈Zctgx = 0x = π/2 + πk, k∈Z