@Kitonum Sure, that will work.  Thanks.  I was more interested, however, in understanding why F(s) yields the wrong result in my original post.

@Markiyan Hirnyk The yellow area in those wiki pages is an artifact of the boxes having unit heights.  Where will the yellow area be if the boxes were of height 2 each?

@Carl Love  Thanks, that's good!  Motivated by what you have shown, I came up with the following alternative:

> F(s);

> subs(s=q, %);

@ANANDMUNAGALA You don't need a different procedure for the inverse interpolation.  What you need is to understand what Neville's inverse interpolation is about (that has nothing to do with Maple) and then apply your existing procedure to do what the inverse interpolation is supposed to do.

@Simon_2604 That 70 kB is much too small.  On Linux I get file of ~2.8MB, as tomleslie does on Windows.  So as you said, you must be getting pretty much an empty file.  I have no idea why that is happening.  As a last resort you may want to contact the Maple Technical Support but I am afraid that the issue may be specific to your machine, in which case they won't be able to help.

As to viewing, tomleslie writes that "it takes ages to load".  That must be a problem with the specific EPS viewer on Windows.  On Linux the image loads in 2 to 3 seconds,  I tried it with three different EPS viewers (gv, evince, display).

@Simon_2604 I have no problem with exporting your plot as EPS in Maple 18 and viewing it.  I export it by right-clicking the figure and selecting Encapsulated Postscript.

I am doing this on Linux, where there are various EPS viewers.  I viewed the saved graph with gv and evince.  Both show the expected image.

@Simon_2604 What is Ysq?  It would be easier to diagnose the problem if you upload your maple worksheet. (Use the large green up-arrow.)

Aside: The following is not the source of your problem, but have a look at the documentation of sphereplot.  You will see that:

Important: The sphereplot command has been deprecated.  Use the superseding calling sequence plot3d(args, coords=spherical), ...

@acer I do sympathize with the sentiments you have expressed.  I do use the F3 and F4 keys to combine/split execution groups in the manner you have described.

I don't know about you, but I have always felt that the behavior of the F4 key is not quite correct.  Ideally, after joining two execution groups with F4, the prompt (>) of the second groups should go away, but it doesn't.  Perhapst the problem that you and the OP have noted stems from that bad design -- that is, Maple gets confused by those spurious prompts.  Redesigning F4's action to remove those out-of-place prompts should make Maple 2015 happy.

@Kitonum You have just helped mish1995 to

1. avoid doing his homework;
2. help him deceive his teacher by passing your solution as his own;
3. get credit for work he didn't do.
   

Is that a good thing to do?

@rightClick The link marked About at the bottom of every Maple Primes page contains a statement of the objectives of this forum.  There is no explicit prohibition there on doing someone else's homework, but most schools do have integrity policies that condemn passing someone else's work as one's own.

I am by no means empowered to enforce guidelines in this forum.  I am merely expressing my opinion.  Specific questions on technical issues regarding Maple, mathematics, programming, or related issues are quite alright in my view.  But saying "if nobody does this for me I will fail, please do this question for me" exceeds the bounds of propriety by any standard.

That convert in essence replaces D with diff, and we do know that diff works.  That doesn't say why D doesn't work.

@Carl Love I posted my That Clarifies reply to Preben before seeing your mesage.  It agrees with what you have written above.

@Preben Alsholm Ah, that clarifies things even more.  When plotting a vertical segment, if the x coordinate's data is fuzzy even a little bit, the horizontal range is set according to the data.  But if the data is absolutely constant, then the horizontal range is set out of other considerations.  For instance, the following command  sets the x range from -1 to 1 although no view is specified:

plot([0,t, t=0..1]);

@Preben Alsholm Of course! Your observations is right on the mark.  Asking Maple to draw a vertical line segment is not enough.  What is it to take for the horizontal range?

I had assumed implicitly that a polar plot will inclulde the origin.  But there is no basis for that assumption.  If we want to inlcude the origin, then we do:

plot([0, 1/cos(t)], t=0..Pi/3, coords=polar);

and get the correct plot.

In view of this, I am now somewhat puzzled with Kitonum's comment whereby the Classic worksheet produces the correct plot.  Perhaps the Classic worksheet includes the origin in a polar plot by default.

Note added a minute later: To counter my own argument, how do we explain this then?

plot([1,t, t=0..1]);

I don't use the Classic interface.  In the regular interface the bug goes back to at least MapleV-R4.   I was reminded of this while cleaning up my old mailbox today.  I had brought this up in the MUG (Maple Users Group -- remember that?) in 1999 (!).   I should have filed a formal bug report then, but I didn't, assuming that Maple developers were reading the MUG messages.

I suspect that Maple developers do read Maple Primes now.  If no one from Maple responds, I will file a formal bug report.