I studiy a classroom  with 3 examples of a positionvector(radiusvector).
The last one a positionvector curve defined by a procedure  in table 3 is not yet working

• see enclosed worksheet : animate(F, [z], z = 0 .. 5, frames = 101) is not working yet

 dr_lopez_Classroom_animatedtrace_radiusvecor_is_positievector-via_Plotpositievector.mw

I must say that using the help for this package is not intuiative. ( in general for all )
Once on a page for command i can't  go back to the home page where the mainpage is for the package
Example i was doing something with gradient command and try figure out how to make a function out of it
 

At the examples nothing to find about this .. via contectpanel : evalVF (evaluate vectorfield)
So i want to look at the eval command in the student vectorcalculus package 
This could be easy if there was a button to see all commands ( a home button) on the gradient page

Now i must type in help again .. 
evalVF gives a column vector notation , but mixing both notations ? ( as vector , as column vector)  
 

gf := Gradient(exp(x*y^3*z^2))   

This i can evaluate via contectpanel for  f(x,y,z)  in a point and as output a colomn vector 

Making a vectorfunction for gf is not possible via contectpanel ? , or do i miss something

Note: perhaps showing the package commands in the working document is a idea 
   

To practice more in documentmode
Given  f := x^2 + y^2 + z^2 = 1  
Asked: 
surfacelevel on level 1  and surfacelevel upon wich the point (sqrt(3), 3, -2) is located.

1) x^2 + y^2 + z^2 = 1   : what solid ( a sphere with radius 1)  and  plot 
2) surfacelevel (solid sphere)   for point  (sqrt(3), 3, -2) and plot
3) Plot together 

Doing this calculation solely with contextpanel..no that's not always possible as it seems by trying to plot a sphere. 

I can use a whole package in a procedure or a command from a package. 
Writing your own code needs sometimes external code from outside a procedure used ( a package..what else more?)
This i don't find back in the Maple helpfiles easily using external code in procedure  
 

 This old example uses display3d naming what is the same as display ( there is no display3d command in Maple ) 
It gives the error 

diskmethod(f,0,2,10,fig);
Error, (in with) package plots does not export display3d

The disk methode calculates 
V = int(Pi*f(x)^2, x = a .. b)

 The Code for diskmethoddisplay

diskmethod:=proc(f,a,b,N,figure::evaln)
  local X,Y,s,x,dX,i,disk;
  with(plots,display3d);
  X:=array(0..N);Y:=array(1..N);disk:=array(1..N);
  dX:=evalf((b-a)/N);
  X[0]:=a;s:=0;
  for i to N do
    X[i]:=a+i*dX; Y[i]:=evalf(f(X[i]));
    s:=s+evalf(Pi*Y[i]^2*dX);
    disk[i]:=plot3d([x,Y[i]*cos(theta),Y[i]*sin(theta)],
                x=X[i-1]..X[i],theta=0..2*Pi,grid=[2,51]):

  end do;
  figure:= display3d({seq(disk[i],i=1..N)},
            axes=box,projection=0.8,orientation=[-60,70]);
  print(`The approximate volume using`,N,`disks is V =`, s);
end proc:

A circle in XOY plane in a 3D axis system
There are two commands :
- spacecurve ( calculus)
- SpaceCurve ( vectorcalculus) 

p1 := plots:-spacecurve([x, sqrt(-x^2 + 1), 0], x = -1 .. 1, color = black, thickness = 5);
p2 := plots:-spacecurve([x, -sqrt(-x^2 + 1), 0], x = -1 .. 1, color = black, thickness = 5);
plots:-display(p1, p2, scaling = constrained, labels = [x, y, z]);

spacecurve plot for circle in parametric form sin(t,cos(t) ?
Spacecurve plot for circle  ( coordinatesystem )?