Question

Let\[S=\{r\in\mathbb{Q}:0 14 years ago

Answer 1

can you tell me what int() and db() denote?

Answer 2

int() denotes the interior points of the set and bd() denotes the boundary points of the set.

Answer 3

There are infinitely many rational numbers in between 0 and root 2 though.

Answer 4

could one of u help me?

Answer 5

please?

Answer 6

maybe im missing the definition, but isnt the rational number 1 in that set? or am I just completely missunderstand the definition "interior point"?

Answer 7

i dont know..

Answer 8

come one on of u who are vewing this question could understand the math im doing.. please help.. come on.

Answer 9

thanks for teh help..

Answer 10

I was taught that a boundary point of\[S\subseteq\mathbb{R}\] is a point\[x\in\mathbb{R}\]such that for every neighborhood N of x,\[N\cap S\neq\varnothing\]and\[N\cap (\mathbb{R}\setminus S)\neq\varnothing\]

Answer 11

ah ok, then its me misunderstanding the definition then.

Answer 12

Also, an interior point of\[S\subseteq\mathbb{R}\]is a point\[x\in\mathbb{R}\]such that there exists a neighborhood N of x such that\[N\subseteq S\]

Answer 13

Since 1 is right on the boundary of S, any neighborhood of 1 will contain points outside of S. Thus it cannot be an interior point.