Imagine I have a variable X

I use plot (X, type="l").

I want to "show" with colour the area between "the line of X" and the Zero
Axis.

So that if X have negative values the colored area will be below zero.

I´m trying to make this with polygons() but I´m not able....

Can you guide me to do it?


The other question is how can I show "the zero axis" in a plot?

	[[alternative HTML version deleted]]


