Cos x=1/2 tg x=-1

Cosx≤ -1/2 ;
2πk+ π - π/3 ≤ x  ≤ π + π/3 + 2πk ;
2πk+ 2π/3 ≤ x  ≤ 4π/3 + 2πk . 
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sinx ≥1/2 ;
2πk+ π/6  ≤ x  ≤ π - π/6 + 2πk ;
2πk+ π/6  ≤ x  ≤ 5π/6 + 2πk .
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tqx ≤ 1 ;
πk  - π/2 ≤ x ≤ π/4 + πk .
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ctqx ≥ -1 ;
πk  +0 ≤ x ≤ π-π/4 + πk ;
πk   ≤ x ≤ 3π/4 + πk.