Need some help using plot 2d



> 
> I'm curious tho. Why "norotate border" ? I tried removing it, and it
> still worked.

These settings correspond to gnuplot defaults and you can remove them. I
copied and pasted the gnuplot code automatically generated by the draw2d
command; they are strictly necessary when you want to change these
defaults.


> The highlighting was not what I was looking for.
> I wanted the highlight circle to be wherever One X num met another Y
> num ( such as -5x&-11y ; 0x&-1y ; 2.5x&4y )

You can store in variable myx the specific x's you want to highlight:

( f(x) := 2*x-1 ,
  myx: [-5, 0, 2.5] ,
  pts : makelist([i,f(i)], i, myx) ,
  wxdraw2d(
     grid = true,
     explicit(f, x, -5, 5),
     xtics = [-5,1,5],
     color = red,
     point_type = circle,
     point_size = 2,
     points(pts)) ) $

In case you have an special interest in x= -5, 0 and 2.5, perhaps this
version is better for you (the trick is a call to function setify):

( f(x) := 2*x-1 ,
  myx: [-5, 0, 2.5] ,
  pts : makelist([i,f(i)], i, myx) ,
  wxdraw2d(
     grid = true,
     explicit(f, x, -5, 5),
     xtics = setify(myx),
     color = red,
     point_type = circle,
     point_size = 2,
     points(pts) ) ) $


If you prefer function plot2d, similar ideas could be applied.

-- 
Mario