1)решите неравенство: cost ≤ 1/3
2)найдите корни уравнения сos(x+pi/12)=0 на промежутке [0;3pi/2]

1cosx≤1/3x∈[arccos1/3+2πk;2π-arccos1/3+2πk,k∈z]2cos(x+π/12)=0x+π/12=π/2+πkx=-π/12+π/2+πkx=5π/12+πk,k∈z0≤5π/12+πk≤3π/20≤5+12k≤18-5≤12k≤13-513≤k≤13/12k=0⇒x=5π/12k=1⇒x=5π/12+π=17π/12