I don't think there is anything wrong with the way you typed it into the email. Are you sure you didn't forget a
bracket in the code?
This plot works fine (I just substituted numbers for your constants, but it does not display points.) So I am wondering
where you get the discrete points from and if they all have values.
plot2d([deltaX(1,2,3,Astep),[discrete,[[1,1],[2,2],[3,3],[4,4],[5,5],[6,6]]]], [Astep,1,6],[gnuplot_curve_styles, ["with
line", "with points"]]);
I am more familiar with draw2d.
try this.
load(draw);
draw2d(color=blue, explicit(deltaX(1,2,3,Astep), Astep,1,6), color=red, point_size=.5,
point_type=filled_circle,points([[1,1],[2,2],[3,3],[4,4],[5,5],[6,6]]));
You will get red points and a blue curve.
Rich