Дам 50 баллов! 1) sin8x < 1/2 2) ctg2x > -1 3) tg3x ≤ -1

Question

Дам 50 баллов!
1) sin8x < 1/2
2) ctg2x > -1
3) tg3x ≤ -1

Answer 1

1)  -7п/6 + 2πk < 8х < п/6 + 2πk → -7п/48 + πk/4 < х < п/48 + πk/4    k∈Z
2) -π+ πk < 2x < -π/4+ πk → -π/2 + πk/2 < x < -π/8 + πk/2  k∈Z
3) -π/2 + πk < 3x ≤ -π/4 + πk → -π/6 + πk/3 < x ≤ -π/12 + πk/3  k∈Z