this is a review problem that I am not sure about.

is the set {(x,y)∈R^(2 ) ∶ 3x^2+ 5y^2=1} a closed set?

my initial thought is yes however I think I am missing something important.

I know that this is an ellipse but it is not in standard form. I had mathlab graph it and it complained that there

complex numubers that it was going to ignore, so I suspect that while the graph appeared to be a solid curve it is actually

full of spaces between the real solutions.

any thoughts?