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.