@mzaman Nobody wants to retype your code. Instead of a screen shot, please post plaintext or upload a worksheet. You can upload worksheets and a few other file types by using the green uparrow that is the last item on the second row of the toolbar in the MaplePrimes editor.

@Kitonum 

Note, however, the significance of round-off. You had to change the OP's 0.36 to 0.3603 in order to get equality. I recommend that the OP work in exact rational arithmetic for such problems. That can be done by not using any decimal points in the input.

@lt I still don't see the problem that is the subject of this Question. The plot shown in your worksheet clearly shows that your textplot3d commands are working.

There is no need for you to direct my attention to your other Questions. I read and consider everything posted on MaplePrimes. 

@UndergradMaths 

Right clicking on the output of your equation brings up a context menu. Select "Solve DE."

If you want to type a command, type dsolve(%);.

@lt Would you please post a worksheet where the above command doesn't work? Your syntax looks fine to me.

What do you mean by "a label coordinate"?

Are the circles in the same plane with one inside the other? On first thought, that seems an easier problem than two arbitrary circles. 

@Axel Vogt

I'm just writing this to clarify Axel's advice: If you want to avoid this anomaly, use 1/10 instead of 0.1. The floating-point anomaly that you point out is just a standard example, not an bug.

@Kitonum I agree with Markiyan. What relation is there between your workaround plot and the matter discussed in the paper which the OP referenced?

@Kitonum Here's another improvement. This avoids the once-per-rotation stutter caused by 0 and 2*Pi being actually the same frame. We start the rotation a little higher than 0 based on the frame count. This improvement can be applied to any continuous-play rotating animation:

Frames:= 54:
plots:-animate(
     plots:-tubeplot,
     [[cos(t+phi), sin(t+phi), t], t= 0..6*Pi, radius= 1/3, numpoints=200],
     phi= (2*Pi)/Frames..2*Pi, frames= Frames,
     orientation= [40,70], shading= z, axes= box, style= patchnogrid,
     scaling= constrained
);

@GPY Right click on the animation. Select the Animation context menu. Check off the option Continuous. This can also be done in the animation toolbar. Use the second pull-down to the right of the slider to choose between Continuous and Single Cycle. All animations start as single cycle. There is unfortunately no way to control this programatically, i.e., with the plot/animation command.

@Kitonum 

In the standard American high-school curriculum, it is usual to indicate a jump discontinuity with a hollow circle on one  piece of the graph and a solid circle on the other piece at the jump point. So, in the case of floor, each segment would have a solid circle on the left end and a hollow circle on the right. Is this possible using option discont? Of course, I can figure out how to explicitly plot the hollow circles; what I want is a way using discont or some such.

@acer The plot can be improved with option discont as in

plot(cos(x)/(x^2+2*x), x= -10..10, discont);

The command smartplot seems to ignore the option: neither results nor an error message appears.

Were you trying to approximate by using a context menu or by a directly typed evalf command?

@GuruYerram The link that you gave works, but there is no file found there. Possibly it has been removed. Even if I shorten it to mkhebcha.math.science.cmu.ac.th/206455, it is not found. Can you just take a photo of the page with your phone and post it?