Question

How do you graph `y=tanx`?

Answer 1

graph{tan x [-10, 10, -5, 5]}. See explanation.

Explanation:

graph{tan x [-10, 10, -5, 5]}

The number of lines you have to draw
depends on the domain provided.
If the domain is not specifically provided, you will have to draw them all (that's what the function does).

If you're doing it by hand,
I would first trace some vertical construction lines (asymptotic lines) at `pi/2`, `-pi/2`, etc..., where `tan x` is not defined.
Then I would plot a few points and try to make the line passing through these points as smooth as possible, and being extra careful not to cross those asymptotic lines.