1)sin2x=sinx2)cosx+2cos^2x=0

1) sin2x=sinx sin2x - sinx = 0 2sinx - sinx = 0 sinx (2cosx - 1) = 0 sinx = 0 => x = pik, kc Z cosx = 1/2 => x = ± pi/3 + 2pik, kcZ --------------------------------------------- 2) cosx + 2cos^2x=0 cosx ( 1 + 2cosx) = 0 cosx = 0 => x = pi/2 + pik, kc Z cosx = - 1/2 => x = ± 2pi/3 + 2pik, kcZ