- #1
bonildo
- 14
- 1
Homework Statement
Hello, I'm not sure if it's the right place to post this exercise, but I'm learning it in a calculus course.
I need to prove that:
a) The complement of an open set is a closed.
b) An open interval is a open set, a closed interval is a closed set.
Homework Equations
I have the following definitions:
1) An subset A⊂R is open if for all sequence {an}n∈N that converges for l∈A,
∃n0 such that ∀n>n0 ,an∈A.
2) An subset A⊂R is closed if for all sequence {an}n∈N that converges for l∈R,
l∈A.
The Attempt at a Solution
I don't have any ideia how to do it , I never worked on this kind of exercise before