jaytreiman

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19 years, 264 days

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These are replies submitted by jaytreiman

@serena88  Attached is a simple example of how one can use the save and read commands.  The anames command can be used to make certain you are saving all of your information.

 

 

restart;

for i from 1 to 10 do
   cat(a,i) := i^2;
   end do;

anames(user);

save i, a10, a9, a8, a5, a4, a7, a6, a2, a3, a1, "temp.m";

restart;
read "temp.m";

a9;

 



Download SaveRead.mw

@serena88  Attached is a simple example of how one can use the save and read commands.  The anames command can be used to make certain you are saving all of your information.

 

 

restart;

for i from 1 to 10 do
   cat(a,i) := i^2;
   end do;

anames(user);

save i, a10, a9, a8, a5, a4, a7, a6, a2, a3, a1, "temp.m";

restart;
read "temp.m";

a9;

 



Download SaveRead.mw

@Dave H 

I find the  statement "The main difference is that the (default) initially presented view is now a lot more visually informative and useful." an overstatement at best.  In the case I have, the growth rate is the important feature.  This is in direct contradiction to your assertion.  The smart view heuristic is simply that, a procedure that often gives more pleasing results, not a procedure that always emphasizes the desired features of a graph.

It may be easier to answer your question if you supply more information.

Are these plots from data?  Is the vertical scale correct or is it simply for offset?

I am sure I am forgetting many pieces of information that would help, but those two would be a start.

@pagan There is not a "correct" viewing window, range and domain set, for most functions.  That has been debated before.  The problem here is that I gave Maple a simple function with no bad behavior and smartview removed an important feature of the function from the plot by changing both the domain and the range.  A plot of exp(x) should show the exponential growth of the function.

I think forcing students to jump through hoops to get a good plot of a simple function is a waste of my time and the students' time.

If you want to get a "good" plot of tan(x) from Maple, you need to know the function is discontinuous.  That information then needs to be put into the plot routine.  I would expect students to get something like the plots below that are from Maple 16.  In either case, some thought is required.  (Having the smatrview routine check for discontinuities is something I think should be debated before being added.)

plot(tan(x),x=-4*Pi..4*Pi,y=-10..10,discont=true);

 

plot(tan(x),x=-4*Pi..4*Pi,discont=true);

 

 

 

Download tan_plot.mw

@pagan   That does the trick. 

@Alejandro Jakubi   In the FAQ on the Maple site there is a note that you need to get it from technical suport.  I contacted them and they e-mailed me the required file with instructions on where to put it.

Finding maxima and minima in Maple can be tricky.  In order to help I would probably need to know:

  1. What type of function you are using.
  2. Do you need an exact answer?
  3. Is this a constrained problem?
  4. Are you setting grad(f)=0 and solving?

With that information, I believe people could start helping you.

If the surface is a level set for a function, of the form F(x)=C, you want to solve the equations in x and λ,

grad F(x)=λ x .

An example would be very helpful.

If one uses the root command instead of 1/3 as the exponent to guarantee that you get the principle root, you get an immediate simplification for

F:= (a-2)/(a-root(8,3));

to 1.  The function form

f2 := a -> (a-2)/(a-root(8,3));

works perfectly at 2, but gives 1 for any variable input.

 

With the first example, if one uses simplify on the denominator for a=1/3 one gets 0.  Shouldn't a check for a zero denominator always be done?

q := (6*((1/3)*a-1/9))/(36*a-116+12*sqrt(12*a^3-3*a^2-54*a+93))^(1/3);
simplify(eval(denom(q),a=1/3));

 

Finally, a question:  Is the basic problem in Maple's evaluation of this expressions that it does not check for a 0 denominator?
 

The "axis" option is avaiable in Maple 10.  What you need to do is list the places where you want the grid lines to be.  Not very nice, but it can be done.

The "axis" option is avaiable in Maple 10.  What you need to do is list the places where you want the grid lines to be.  Not very nice, but it can be done.

I still am getting a border with the commands: plotsetup(ps,plotoutput="twoexponent.eps",plotoptions="width=2.5in,portrait,noborder"); plot(2^x,x=-3..3,gridlines=true,title=typeset(y=2^x),scaling=constrained); This is with Maple 11 on SUSE 10.2.
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