Prove that $\mathbb{Q}^n$ is a countable dense set in $\mathbb{R}^n$
92740
prove that $\mathbb{Q}^n$is dense subset of $\mathbb{R^n}$
50934
Let $x_n \in[0,1)$ s.t $x_n - \sqrt{n}\in \mathbb{Z}$. Prove that $X=\{x_n | n\in \mathbb{N}\}$ is dense in $[0,1]$.
98755
How can I show that the set of rational numbers with denominator a power of two form a dense subset of the reals?
139247
Real Analysis - Prove a set is countable
4602
Outline of a proof that $\mathbb{R}^2 - A$ where A is countable is path-connected
118595
Proving that a set is countable by finding a bijection
132778
All distances are rational prove the set is countable
43268
How to prove that the set of rational numbers are countable?
127678
A partition of the unit interval into uncountably many dense uncountable subsets
14048
Proof that the complement of zero-measure set on $[0,1]$ is dense in $[0,1]$
106434
Prove that for a dense set $A$ and an open set $U$, $U\subset \overline{A\cap U}$
150337
Let $K$ be a subfield of $\mathbb{C}$ not contained in $\mathbb{R}$. Show that $K$ is dense in $\mathbb{C}$.
120522
Showing any countable, dense, linear ordering is isomorphic to a subset of $\mathbb{Q}$
7402
Showing a compact metric space has a countable dense subset
120273
Showing that a collection of sets is a $\sigma$-algebra: either set or complement is countable
158582
Prove that $\{\frac{\phi (n)}{n}\}_{n \in \Bbb N}$ is dense in $[0,1]$
41192
Neatest proof that set of finite subsets is countable?