Bài 1,
a, 2sinx - 1 = 0
<=> sinx = 1/2
<=> sinx =sin π/6
<=> x = π/6 + k2π hoặc x = 5π/6 + k2π
b, sin ( 2x - π/4) = sin ( x + π/6)
<=> 2x - π/4 = x + π/6 + k2π
Hoặc 2x - π/4 = π - x - π/6 + k2π
<=> x = π/12 + k2π
Hoặc x = 13π/36 + k2π/3