найдите область определения функции 1)y=1/cosx 2)y=tgx/3

1cosx≠0⇒x≠π/2+πn,n∈zx∈(-π/2+2πn;π/2+2πn,n∈z ) U (π/2+2πn;3π/2+2πn,n∈z)2-π/2+πn<x/3<π/2+πn-3π/2+3πn<x<3π/2+3πnx∈(-3π/2+3πn;3π/2+3πn,n∈z)