cosx = -

/2x = pi - arccos

/2 + 2pKx = pi - pi/6 + 2pkx1 = 5pi/6 + 2pkx2= -pi + pi/6 + 2pkx2 = -5pi/6 + 2pksin2x = - 12x = (-1)^karcsin(-1) + pK2x= 3pi/2 + pkx = 3pi/4 + pk/22ctg3x = -2ctg3x = -2/2ctg3x = -13x = arcctg(-1) + pk3x = -arcctg1 + pk3x = -pi/4 + pkx = -pi/12 + pk/3sinx <= 1/2 x ∈ [ -pi - arcsin1/2 +2pk; arcsin1/2 + 2pk]x ∈ [ -pi - pi/6 + 2pk; pi/6 + 2pk]x ∈ [ -7pi/6 + 2pk; pi/6 + 2pk]cosx =>-√3/2x ∈ [arccos√3/2 + 2pk; -arccos √3/2 + 2pk]x ∈ [ pi/6 + 2pk; -pi/6 + 2pk]