2sin2x-1=0
напомощь+++++++

2sin 2x -1 = 02sin 2x = 1sin 2x = 1/22x = { π/6+ 2πn, n∈Z        { 5π/6+2πn, n∈Z  <=> (-1)^{n}*π/6 + πn,n∈Z     | :2 x = {π/12 + πn, n∈Z       {5π/12 + πn,n∈Z   <=>  (-1)^{n} * π/12 +πn/2, n∈Z