spradlig

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16 years, 187 days

MaplePrimes Activity


These are replies submitted by spradlig

@acer 

Thanks.  I don't have Maple 18, but I wrote a worksheet a lot like your example in 17, and it works.

@acer 

 

What you describe is exactly what I've been looking for recently.  I want to be able to create Maple worksheets that can be posted online and run by someone with MaplePlayer or just with a browser (not requiring a plug-in would be great).  Your answer gives me an idea of where to start.

I have a question for you: before I reinvent the wheel, do you know if anyone has done this already?  I don't want to reinvent the wheel.

 

Greg Spradlin

Embry-Riddle University

Daytona Beach, FL

@Carl Love 

 

Works like a charm.

@Kitonum
Thanks.  I clicked on your link for your "Picture" procedure and you do things much more impressive than what I'm trying to do.

@Markiyan Hirnyk Thanks.  I gave that exact definite integral as a quiz today.  Many of the students did not know how to convert the integrand to x^alpha form and thus couldn't do the integral.

@pagan 

Does your suggestion:

plotsetup(ps, plotoutput=cat(kernelopts(homedir),
                             "/My Documents/bypd.ps"),
          plotoptions="noborder,height=200,width=500");


create an .eps file?



I'm a mathematician, and I don't really know the difference between a PostScript file and an encapsulated
PostScript file.


GS

 

@Mac Dude 

Thanks.  File size is not an issue for me, but image quality is (your answer suggests Photoshop might degrade the quality). and I have a coauthor who really wants an eps file.  There will be no text in the image.  Do you know if it is possible to export the plot image as a bitmap or some other format, use Microsoft's "paint" or some utility that normally comes with Windows (I use Windows, not Mac), and save the result as an eps?

Sorry, everyone else, this is not really a Maple question anymore.

@pagan 

 

Until your comment, the only way I knew how to export a plot was by right-clicking, etc.  If I follow your suggestion (I haven't had time to try it yet), is there a way other than trial-and-error to determine a good height and width?

@Carl Love 

Thanks, I'll modify my file and see what happens.

Using the same string (in this case "slope") for two different things seems like a dangerous idea, period, in any programming language, and I was careless to do so.  I'll change it. 

@nm 

 

I encountered the same problem (a text-based plot) using Maple17 with a different worksheet on my home computer.  It only happened once and did not reappear, so I did not investigate the problem.

@spradlig 

 

Guys:

I made a hard copy of my question and the angle does look like a right angle (though it doesn't on my computer).  Maybe the settings on my computer monitor are off.  Sorry for bothering you with a rather silly question.

GS

@Joe Riel 

 

Both on the Web page and in the Maple worksheet, it looks clear to me that the angle is obtuse.  Notice that the 0.5 * 0.5 grid squares that appear in my question (but not in my worksheet when I execute it on my computer) are wider than they are tall.  Is there any way for me to prove that I am not imagining this?

 

GS

@Carl Love : Your posts are always informative.  However, I did not ask maple to calculate N^(1/3) for an extremely large integer, I asked Maple to find 8^(1/3), and it failed.  In Mathematica, I set n = 10^1002, asked for n^(1/3), and Mathematica returned a very large power of 10.  It took no time at all.  I did not count the digits, but I would bet my left arm the answer is correct.  Score one for Mathematica.

Also, for real N, if no other context is given, N^(2/3) is by definition the square of the real cube root of N, so I'm not sure why Maple forces you to use "surd" if you want to find N^(2/3).  With my n=10^1002 from above, Mathematica also found n^(2/3) instantly, so there is probably a way the maplesoft people can fix this behavior.

Perhaps Maple should test if a quantity is likely to have a simple cube root and if so, compute it, rather than failing on extremely easy problems.

I don't understand why Maple and Mathematica both fail to graph x^(2/3) correctly.  Every good calc student knows how to graph that.  If you are plotting a function of a real variable in the Cartesian plane, you don't mess with complex numbers at all unless you have a good reason.  For real x, x^(2/3) is the square of the real cube root of x.  One could provide excuses for both Maple and Mathematica, but the fact is, Maple and Mathematica are producing incorrect graphs.  I think both languages are supposed to be easy for people to use, and not optimized so computers can use them (which might be at least partially true for C/C++, for example).

If Maple can do sophisticated mathematics correctly, it should be able to do basic mathematics correctly.  A student or professor should be able to plot x^(2/3) in Maple without messing with initialization files or using additional commands.

I have never edited an initialization file, and I would bet that a tiny fraction of Maple users have.  One cannot expect students to do it on their own computers (you can't even expect them to change Maple's newer default settings to better ones).  If one uses Maple on multiple classroom computers, it may be impractical.  If one is using Maple installed on a central server, it may be difficult or impossible without assistance from one's IT department. 

I like Maple, and I prefer it to Mathematica, but I won't let brand loyalty prevent me from complaining about what seem to me to be obvious flaws, and seeking solutions.

 

GS

 

 

 

@Carl Love : Thanks for the extra information.  Note my comment above.  I dislike Mathematica, but it computes 8^(1/3) and 8^(2/3) correctly without my having to jump through any hoops.  However, like Maple, it will not plot x^(2/3) from -1 to 1.

I think it is ab"surd" that I should I have to learn more commands and/or options just to make Maple return values or plot functions that we would expect any Calc I student to be able to do (unless it is difficult to program Maple to do this.  The fact that Mathematica seems to t least handle fractional exponents better than Maple suggests that the maplesoft people should be able to fix this problem).

In case anyone is curious, I tried Mathematica and it gave me the correct answers (4 and 2) when I asked it to compute 8^(2/3) and 8^(1/3), without my having to jump through any hoops.  But just like Maple, it plotted x^(2/3) only for positive x (when I attempted to plot it in the obvious manner without using any options or additional commands).

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