1. 1) ctg x = 1; x ∈(- π; 2π).
x = π/4 + πk; k∈<span>Z
x= - 3</span>π/4; π/4; 5<span>π/4.
2) ctgx = - </span>√3; x∈(- π; 2<span>π).
</span>x = - π/6 + 2πk; k ∈Z.
x = - π/6; 5<span>π/6.
</span>
2. 1) ctg x < - 1;x∈(- π; 2π).
- π/4 < x < 0 U 3π/4 < x < 2π U 7π/4 < x < 2<span>π.
</span>2) ctg x ≥ - √3; x ∈ ( - π; 2<span>π).
</span>- π ≤ x ≤ - π/6 U 0 ≤ x ≤5π/6 U π ≤ x ≤ 11 <span>π/6</span>
Сos2a=1-2sin²a
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14.15-11.45=2.30 минут был включен принтер
80:2=40 cнимков в 30 минут
80+80+40=200 снимков