Let

Determine whether A is open, closed or neither. What is the closure, interior and boundary of A?

I was under the impression that the set is neither open nor closed, but am struggling to prove this.

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- June 22nd 2011, 10:58 AMCairoOpen or Closed?
Let

Determine whether A is open, closed or neither. What is the closure, interior and boundary of A?

I was under the impression that the set is neither open nor closed, but am struggling to prove this. - June 22nd 2011, 11:14 AMPlatoRe: Open or Closed?
- June 22nd 2011, 02:32 PMDevenoRe: Open or Closed?
you might want to consider the following subsets of :

{0}x[0,5], {3}x[0,5], [0,3]x{0}, [0,3]x{5}.

which of these are entirely in A?