I'm looking to plot individual vectors (not a field) for an equilibrium lab using some type of free online site or tool. I've googled for a while and found nothing.
where (0,1) is the initial point and (2,3) is the terminal point. Several arrows can be drawn at once:
Here the addition sign is simply superposition of plots, not addition of vectors. Of course, Sage can add the components too.
Alternatively you could try an applet such as this one, but the ones I saw were either rudimentary, or emphasized geometric manipulations over the numerical values of components. Not to mention that Java is evil.