Quite accidentally I discovered incorrect calculation of the simple definite integral:

int(1/(x^4+4), x=0..1);

evalf(%);

1/8*ln(2)-1/16*ln(5)+1/32*Pi+1/8*arctan(1/3) # This is incorrect result

0.1244471178

Is this a known bug?

If first we calculate corresponding indefinite integral, and then by the formula of Newton - Leibniz, that everything is correct:

F:=int(1/(x^4+4), x):

eval(F, x=1)-eval(F, x=0);

1/16*ln(5)+1/8*arctan(2)

0.2389834593

I am currently working on an adaptive question in Maple TA 2016 and it seems that there is a bug in the drop - down list functionality:

After I click "Verify" in a section, the answer disappears even though I choose it to be displayed. The window simply goes back to showing (Click for List) instead of keeping the answer, see the screenshot below.

Perhaps I am doing something wrong, though I have used Lists extensively in the previous version and never had that problem ..

Thanks for your help!

Elisabeth

Hello All,

(I also sent this fact to Maplesoft Support).

Since I updayed to 2016.1 the F1 key does bring a menu witch send to..F5 only.

No way to have a "full" Help Menu.(See the attached file)

I guess a silly bug jumped in :)

Kind regards,

Jean-Michel

Hello there! Maple 2016.1 sometimes gets crasy about parsing input strings. I managed to capture this behaviour in the attached file. It looks like below. I am not sure what exactly triggers it. It just starts happening all of a sudden. What might be the cause...?

Error, incorrect syntax in parse: `;` unexpected (near 4th character of parsed string)

Error, invalid semantics "π"

Download test.mw

This question is related to the recent post http://www.mapleprimes.com/questions/211460-Series-Of-Bessel-Functions1. Consider the following fast convergent series:f:=n->(-1)^(n+1)*1/(n+exp(n));S1:=Sum(f(n),n=1..infinity);evalf(S1);S2:=Sum(f(2*n-1)+f(2*n),n=1..infinity);evalf(S2);As expected, the sum of the series is obtained very fast (with any precision), same results for S1 and S2.2. Now change the series to a very slowly convergent one:f:=n->(-1)^(n+1)/sqrt(n+sqrt(n));evalf(S1) is computed also extremely fast, because the acceleration algorithm works here perfectly.But evalf(S2) demonstrates a bug:Error, (in evalf/Sum1) invalid input: `evalf/Sum/infinite` expects its 2nd argument, ix, to be of type name, but received ...3. Let us take another series:f:=n->(-1)^(n+1)/sqrt(n+sqrt(n)*sin(n));Now evalf(S1) does not evaluate numerically and evalf(S2) ==> same error.Note that I do not know whether this series is convergent or not, but the same thing happens for the obviously convergent seriesf:=n->(-1)^(n+1)/sqrt(n^(11/5)+n^2*sin(n));(because it converges slowly (but absolutely) and the acceleration fails).I would be interested to know a method to approximate (in Maple) the sum of such series.

Edit. Now I know that the mentioned series

converges (but note that Leibniz' test cannot be used).

eulermac(1/(n*ln(n)^2),n=2..N,1); #ErrorError, (in SumTools:-DefiniteSum:-ClosedForm) summand is singular in the interval of summationeulermac(1/(n*ln(n)^2+1),n=2..N,1); #nonsense

Hi,

When I execute the command

series(exp(x),x)

and then refer to the equation in a new execution group using a equation label (CTRL-L on Windows), the equation is shown in Maple 18, but in Maple 2015 I get an error message: 'Error, missing operator or ';'. Using the % instead does work for both versions.

Is this intended behaviour or a bug in Maple 2015?

Thanks,

Bart

in LinearAlgebra Eigenvectors calculation.

So the above output startled me. I have used the Maple Linear Algebra Eigenvalues, Eigenvectors commands many times with no problem. Can any one explain to me what is going on. The program correctly calculates the eigenvalues for the matrix which are all distinct for a real symmetric matrix, and thus should have three distinct non-zero eigenvectors, yet the eigenvectore command returns only zeros for the eigenvectors. I calculated an eigenvector by hand corresponding to the eigenvalue of 1 and obtained (1, -sqrt(2)/sqrt(3), -1/sqrt(3).

So this is either a serious bug or I am going completely insane.

Found a strange behaviour in Mapke 2015 of the sqrt-function after loading the GRTensor package:

the square-root of a non-square integer, e.g. sqrt(5), does not terminate. 5^(1/2) instead works fine.

Can be reproduced with Maple 18, but not with Maple 11.

I consider this a serious bug, as it makes any expressions containing such roots useless.

As it worked with Maple 11 I am inclined to see it as your fault.

In the running of an example I faced to computation of radical ideal of the following ideal:

<-c*m*u+d*c*n+m*b*v+m*c*t>

I used from Radical command in PolynomialIdeals package. But I dno't now why it's computation is very hard and Time-consuming?

What I have to do? I think there is a bug, since this ideal is simple, apparently.

In Maple 2015.1 we have

restart;

solve([sin(2*x)/cos(x+3*Pi/2)=1, x>-4*Pi, x<-5*Pi/2], x, allsolutions, explicit);

solve([sin(2*x)/cos(x+3*Pi/2)=1, x>0, x<2*Pi], x, allsolutions, explicit);

In the first example, the error message is not clear (actually there exists a unique root x=-11*Pi/3), in the second example, one root (x=5*Pi/3) is lost.

Has anyone tried to run the following in Maple command-line mode (i.e. in terminal window, type "maple" to start it without the graphic interface),

"

expr1:=t1+t2+t3+t4+t5+t6+t7+t8+t9+t10+t11+t12+t13+t14+t15+t16+t17+t18+t19+t20+t21+t22+t0-t0+t23;expr2:=t1+t2+t3+t4+t5+t6+t7+t8+t9+t10+t11+t12+t13+t14+t15+t16+t17+t18+t19+t20+t21+t22+t0-t0+t23;print(expr1-expr2);

Surprisingly, I didn't get "0" with my Maple 17 (under Linux platform) or 18 (under Mac OSX platform). Can anyone help me confirm this?

I'm trying to solve this PDE, and Maple 2015 gives me a solution quickly. I can test the solution with pdetest() and this verifies that it works. However, when I try to verify this myself I don't get zero. Is there some trick pdetest() is using to that I am missing? Or is pdetest() wrong in this case?

eq := I*exp(-(2*I)*k*t)*k*sin(theta)*r^2*cos(theta)^3+4*exp(-(2*I)*k*t)*r*cos(theta)^3+2*(diff(Vr(t, r, theta), theta, theta))*cos(theta)*exp(-I*k*(sin(theta)*r+t))-6*(diff(Vr(t, r, theta), theta))*sin(theta)*exp(-I*k*(sin(theta)*r+t))-4*Vr(t, r, theta)*cos(theta)*exp(-I*k*(sin(theta)*r+t))-4*exp(-(2*I)*k*t)*r*cos(theta);

sol := pdsolve(eq);

pdetest(sol, eq);

eq2 := eval(eq, Vr(t,r,theta) = rhs(sol)): eq2 := simplify(%);

evalb(eq2 = 0);

Download PDESolving.mw

I think that I found a bug in Maple! Please run the following command:

I need the Generators of above Ideal. What is your idea?!

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