hi!

what is the easiest way to prove that the set A is closed and the set B is not closed?

1). A={(x,y) ∈ R²: x²+y²=1}

and

2). B={(x,y) : ∈ R²: x² - y²=1}

Help please. thanks(Shake)(Shake) please

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- May 24th 2011, 12:15 AMsorv1986how to prove a closed set in Rⁿ
hi!

what is the easiest way to prove that the set A is closed and the set B is not closed?

1). A={(x,y) ∈ R²: x²+y²=1}

and

2). B={(x,y) : ∈ R²: x² - y²=1}

Help please. thanks(Shake)(Shake) please - May 24th 2011, 12:18 AMDrexel28
- May 24th 2011, 12:50 AMsorv1986thanks for ur response sir
oho....actually the 2nd one i think its a hyperbola...so it should be not closed...am i wrong?.....but in the first case...i did not understand what r u actually doing to prove that set A is closed