Cos x< =-1/2 sinx> =1/2 tg x< =1 ctg > =-1

Cosx≤ -1/2 ;
2πk+ π - π/3 ≤ x  ≤ π + π/3 + 2πk ;
2πk+ 2π/3 ≤ x  ≤ 4π/3 + 2πk . 

sinx ≥1/2 ;
2πk+ π/6  ≤ x  ≤ π - π/6 + 2πk ;
2πk+ π/6  ≤ x  ≤ 5π/6 + 2πk .

tqx ≤ 1 ;
πk  - π/2 ≤ x ≤ π/4 + πk .

ctqx ≥ -1 ;
πk  +0 ≤ x ≤ π-π/4 + πk ;
πk   ≤ x ≤ 3π/4 + πk.