решить неравенство.
1. 14cos^2(x+p/4)=>0
2. ctg3x=>0

1)14cos²(x+π/4)≥0

cos²(x+π/4)≥0
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2)ctg3x≥0

πn≤3x≤π/2+πn

πn/3≤x<π/6+πn/3;n€Z