Question

найдите область определения функции у=10-√cos х/3

Answer 1

cosx/3≥0
-π/2+2ππn≤x/3≤π/2+2πn
-3π/2+6πn≤x≤3π/2+6πn
x∈[-3π/2+2πn;3π/2+6πn]