Plot a single point on number line in interval notation For example, I want to plot the solution set $\{3\}\cup (2, \infty$). How do I represent 3 as a single point?

If you needed to represent $\{2\}\cup(4,\infty)$, then you could use a filled-in dot for individual points, so you might draw something like the following:

As Alex G. mentioned, since $3$ is in $(2,\infty)$, $\{3\}\cup(2,\infty)=(2,\infty)$ so you wouldn't have to do this for the case you mentioned in your original question.
