The vector field is just a sample, I came to that formula following a false trail that it is embarassing to recall. The Pi/10 simpliy means that I divide the interval between 0 and 2Pi into 20 parts.
You can always resort to graphic primitives:
f[x_, y_, z_] := {x + y, y - z, x^2 + 2 z}; r[t_] := {Sin[t], 0, Cos[t]}; Graphics3D[Table[Arrow[Tube[{r[t], r[t] + f @@ r[t]}]], {t, 0, 2 Pi, Pi/10}]]
Thanks so much for your response, it was a great help. However, I do not understand where the vector function came from on the 1st line of your solution - {x + y, y - z, x^2 + 2 z}, and the Pi/10 as your last entry.
Thanks again. It is apparent that you have an excellent knowledge of both mathematics and the programming language. I certainly appreciate your help.
Mitch Sandlin
