1+ctg2x=1/cos (3 п/2-2x)

1+ctg2x=-1/sin2x

sin2x/sin2x + cos2x/sin2x + 1 / sin2x = 0

sin2x+cos2x+1=0

cos^2 x - sin^2 x + 2 sinxcosx + cos^2x + sin^2x=0

2sinxcosx+2cos^2x=0

2cosx (sinx+1) = 0

cosx=0

x=П/2 + Пn

sinx=-1

x = - - П/2 + Пn