Alex Smith

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16 years, 359 days

MaplePrimes Activity


These are answers submitted by Alex Smith

Maple has never been supportive of LaTeX, and so as Jakubi says, it's not worth it. Not only is the "latex" command severerly out of date and dysfunctional, they have gone out of their way to make it impossible to use psfrag to touch up Maple-produced graphs with LaTeX. I've started using Matlab or pstricks when I have a need to mix LaTeX and graphics.

Perhaps this will help.

with(plots):with(plottools):


F:=transform((x,y)->[x,x*y]):


plot3d(0,x=-1..1,y=-1..1,color=x,orientation=[-90,0],axes=boxed);G:=%:

plot3d(0,x=-1..1,y=-1..1,color=x,orientation=[-90,0],axes=boxed)


display(F(G));

plots[display](plottools[transform]((x,y)->[x,x*y])(plot3d(0,x=-1..1,y=-1..1,color=x,orientation=[-90,0],axes=boxed)))

Try this algorithm

$a=range(3,10);
condition:not(eq($a,0));
$c=range(-7,7);
$b=maple("$a/2*($c)");
condition:not(eq($b,0));
condition:not(eq($b,1));
condition:not(eq($b,$a));
condition:not(eq($b,-$a));
$re = maple("MathML[ExportPresentation]( ($a*(X[n]))+($b*(X[n-1])) =0)");
$s=maple("$b/$a");
$ans=maple("A*($s)^n");

with grading code

evalb($ans=($RESPONSE))

Maybe the key issue is how $s in the above is defined using Maple, and not with the old system that MapleTA is built on top of.

Try something like this:

 

plots[animate](plot3d,[[r*cos(theta), r*sin(theta), u(r,t)], r=0..1, theta=0..2*Pi], t=0..1);

If I enter the following problem verbatim into Wolfram Alpha, it does not produce the correct answer.

"Find the flux of the vector field =F(x,y,z)=x*i-y*j+z^3*k through the sphere with radius 3 centered at the origin."

Of course if the student manages to set up the intergral correctly, then I would expect that they might use Maple to evaluate the integral, and that's fine with me. (They will also use Maple to evaluate the integral even if they set up the integral incorrectly.) Some students might set up a double integral, others will use the divergence theorem. This is the valuable part of learning process.

Using the chain rule, it should be straightforward to get a plot of U as  function of xi and eta as indicated below.

But I don't see how you are going to get a plot in terms of x and y because it's not easy to solve for xi and eta in terms of x and y.

 

U :=(x,y,t)->2*diff(p(x,t),x)*diff(q(y,t),y)/(p(x,t) + q(y,t) + a[0])^2;

p :=(xi,t)-> -k[1]*(3+2*k[2]*k[4]+k[2]*k[4]*sech(k[2]*xi-k[3]*t)^2)*tanh(k[2]*xi-k[3]*t)/(3*k[2]);
q :=(eta,t)-> -l[1]*(3+2*l[2]*l[3]+l[2]*l[3]*sech(l[2]*eta)^2)*tanh(l[2]*eta)/(3*l[2]);

X:=xi-> xi+k[4]*tanh(k[2]*xi-k[3]*t);
Y:=eta-> eta+l[3]*tanh(l[2]*eta);

top:=diff(p(xi,t),xi)/diff(X(xi),xi)*diff(q(eta,t),eta)/diff(Y(eta),eta);
bottom:=(p(X(xi),t)+q(Y(eta),t)+a[0])^2;

plot3d(top/bottom,xi=a..b,eta=d..e);

If the question is simply "Is there a command for diagonalizing of matrices?" then the answer is "yes." Look at the command JordanForm in the LinearAlgebra package.

If a matix is diagonalizable, then the diagonal form is the Jordan form.

 

Try putting in * after the k

int((k*(1-x+.3*x*ln(x))+a)^2,x = s .. 1);

Without this multiplication, Maple thinks you are trying to integrate some unspecified function. Compare

int(k(x),x) with int(k*(x),x)

 

 

You could more directly plot the inverse by

plot( [ g(y), y,  y=0.1..10],labels=[x,y]);

 

Note plot( f(x), x=a..b) is shorthand for plot( [ x, f(x), x=a..b]);

 

Paul,

It's clear as day that Maplesoft did not test the new MapleTA Question Bank Repository structure with real users before pushing out MapleTA 5. If they did, then certainly they would have noticed the problem of question bank flattening and other issues that you point out.

I was amused at the Maplesoft response to your problem (1) pertaining to problems with instructors retaking an assignment.

They responded with puzzlement as to why an instructor would be taking an assignment in the first place. With this perspective, it is no wonder that they would not think to test the new Question Bank Repository structure with actual users.

This seems to work:

 

Digits:=200;

inv_erf := x->fsolve(erf(y/sqrt(2))=x,y,fulldigits);

inv_erf(1-10^(-20));

9.336...

If you take the square root of 2 out of the above defintion of inv_erf, the results are consistent with what WolframAlpa gives with InverseErf.

 

What occurs to me is to convert the list L to a set, which removes duplicates, then convert back to a list.

convert(L,set);convert(%,list);

When I paste you code in the MapleTA 5 question bank editor, it does not work because I suppose it is too much of a skeleton. Below is the code for a mutipart question (4 parts) that uses the same $A in all parts, and it works fine, so it can be done. Maybe this example will be useful.

mode=Multipart@
name=Multipart - Divided corral@
comment=@
editing=useHTML@
solution=@
algorithm=$A=range(20,35,5);
$c1=range(5,15);
$c2=range(25,35);
$C=maple("proc(x) 2*$c1*$A/x+2*$c1*x+$c2*x end proc ");@
question=A rectangular corral of $A square feet is to be fenced off and then divided by a stone fence into two sections. The outer fence costs $c1 dollars per feet, while the special dividing stone costs $c2 dollars per feet.@
weighting=1,1,1,2@
numbering=alpha@
part.1.name=part 1@
part.1.maple_answer=$ans;@
part.1.editing=useHTML@
part.1.question=If x is the length in feet of the dividing fence, the what is the length (in feet) of other dimension of the corral? Enter an expression in the variable x.@
part.1.comment=The answer is $ansml.@
part.1.mode=Maple@
part.1.algorithm=$ans=maple("$A/x");
$ansml=maple("printf(MathML:-ExportPresentation($ans))");@
part.1.maple=evalb(($ANSWER)-($RESPONSE)=0);@
part.1.type=formula@
part.2.name=part 2@
part.2.maple_answer=$ans;@
part.2.editing=useHTML@
part.2.question=Let C(x) is the total cost of the fence in terms of x.<p> Write an expression in x for C(x).@
part.2.comment=The answer is $ansml.@
part.2.mode=Maple@
part.2.algorithm=$ans=maple("$C(x)");
$ansml=maple("printf(MathML:-ExportPresentation($ans))");@
part.2.maple=evalb(($ANSWER)-($RESPONSE)=0);@
part.2.type=formula@
part.3.name=part 3@
part.3.maple_answer=$ans;@
part.3.editing=useHTML@
part.3.question=Write an expression in x for the derivative C'(x).@
part.3.comment=The answer is $ansml.@
part.3.mode=Maple@
part.3.algorithm=$ans=maple("diff($C(x),x)");
$ansml=maple("printf(MathML:-ExportPresentation($ans))");@
part.3.maple=evalb(($ANSWER)-($RESPONSE)=0);@
part.3.type=formula@
part.4.name=part 4@
part.4.maple_answer=$ans;@
part.4.editing=useHTML@
part.4.question=If dimensions are found so that the total cost is minimized, then what is the length (in feet) of the stone wall?

 

 

 

The situation you describe is all too familar, and you describe it perfectly! Techical Support always ignored my inquiries on this matter. Typical.

But I have not encountered this problem with MapleTA 5, yet it was a real headache in MapleTA 4.

When this happened, I removed/deleted the user. Things usually worked out by some miracle.

 Sometimes students enroll in a class and the system manages to classify them as a "guest" instead of a "student." The correlation between this and the situation you describe is positive.

Unfortunately we removed MapleTA 4 from our server. But I distinctly remember encountering the problem with both  course modules  question bank exports.

Here is the email I received from Technical Support on Sept. 2, 2009. You would think that if the fix was as simple as you suggest, then the message would have pointed me in this direction. The message from Technical Support explicitly says, " there isn't anything you can do to correct this right now."

......

Sept 2, 2009 email from Technical Support:

Hi Alex,

it actually looks like these changes were unintentionally introduced in to TA 5 - the import simply skips the Question Bank level of the module structure and creates groups starting from topics.

Unfortunately because the import skips these levels there isn't anything you can do to correct this right now and that we're going to have to create a hotfix to address the issue and restore the desired behavior. 

Of course to answer your question you can unzip course modules to edit the question banks. They are contained in the qbanks folder and do not have extensions but are plain text files.

I apologize for any inconvenience that this causes you, we hope to have a hotfix for this available as soon as possible.

Regards,

Ian
Maplesoft Technical Support

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