Look at the following code:

M1 := (t,lambda1,k,lambda2) -> exp( -(1/2)*(log(1-2*lambda1*t) + k*log(1-2*lambda2*t)) )

int( diff(M1(z,2,9,1/2),z)/sqrt(abs(z)),z=-infinity..0 )/GAMMA(1/2) 

simplify(%)

evalf(%)

returns:    -4.682354481-5.587737200*I

which cannot be true. 

I tried a number of "simplify" options, none of which yielded the desired simple result.

In Maple12 and 2017 we can load a .wav file and Preview no problems. 

The problem occurs when we apply a moving average from the Statistics package and then attempt to Preview the result. Warning - if you don't limit the size of the number of elements when executing the Preview you will freeze and lock up your computer as it attempts to output to the display the errors on each element.

For example.

Using the windows Ding.wav

with(AudioTools):
a:=Read("c:/test/Ding.wav"): #just a random test location I have the Ding.wav file in.
b:=ToMono(a): #changing to Mono.
c:=b^2: #squaring the signal.

with(Statistics):

d:=MovingAverage(c,30):

Preview(d[1..5]) #selecting a small number of values so I don't lock up my system.

Now Preview(d) works in M12 (ie there were no errors and a plot was presented). 

Why doesn't this work in 2017? 

Hello,

I need to construct a sequence of matrices of different sizes, but with similar structure, and to study their determinants etc.

I wrote the following code:

restart: with(LinearAlgebra):
for n from 5 to 8 do:
for i from 1 to n do for j from 1 to n do A[i,j]:=0 od: od:
for i from 1 to n-1 do A[i,i+1]:=3 od:
for i from 1 to n do A[i,i]:=4 od:
for i from 2 to n do A[i,i-1]:=5 od:
A:=([seq([seq(A[i,j],j=1..n)],i=1..n)]);
Determinant(evalm(1-t*A));
od:

However, I get the following error message: "Error, out of bound assignment to a list".

If I add evalm to A:=..., it changes to "Error, 2nd index, 6, larger than upper array bound 5".

I don't see why. I think that by the moment that i and/or j can assume 6, n is already 6.

So what is wrong, and how can this be fixed? Thanks in advance.

I wish to solve three linear simultaneous equations and obtain the solutions in floating point form.

the following works...

solvec:=fsolve({T+N1-m1=0, N2-N1-m2=0,T-N2-m3=0}, {T,N1,N2});

...but the solutions are given in either symbolic, or equation form.  I would like numbers - floating point form.

Below is my attempt to solve this.  with(plots) & with(plottools) is not necessary for this - but I was doing some related graphic work.  I did try with(RealDomain), but it seemedto make little difference.  I have done a copy & paste of an rtf file, but the Maple output has not come out so well.  Any help would be appreciated. 

> restart:

with(plots):

with(plottools):

with(RealDomain);

#Masses in kg (or pounds!)

m1:=70.0:m2:=25.0:m3:=3.0:

#Equations

solvec:=fsolve({T+N1-m1=0, N2-N1-m2=0,T-N2-m3=0}, {T,N1,N2});

#Above gives the solutions in symbolic or equation form, as well as putting the solutions in a set.  How can the programme distinguish between the various values?

# From here is my attempt to form floating point values – to no avail.

NTab:=convert([solvec],table);

N1A:=evalf(solvefor[N1](T+N1-m1*g=0, N2-N1-m2*g=0,T-N2-m3*g=0));

N1B:=convert(N1A, float);

#Problem to isolate the solutions in the vector in floating form,

#and also get the correct ones.  NB the solution is a set - not an ordered list.

maxvec:=max(solvec[1],solvec[2],solvec[3]);

#maxvec:=convert(max(solvec[1],solvec[2],solvec[3]), float);

maxvec:=convert(solvec[2], float);

solvec[2];

whattype(solvec[2]);

type(N2,symbol);

type(solvec[2],equation);

N2_fl:=evalf(solvec[2]);

N2_fl:=convert(solvec[2], float);

N3:=N2_fl+3;

#Actual true answers

#T:=(m1+m2+m3)/2;

#N1:=(m1-m2-m3)/2;

#N2:=T-m2;

OUTPUT:

Error, (in simpl/max) arguments must be of type algebraic

Error, (in simpl/relopsum) invalid terms in sum

Is there a way for Maple to tell where the error occurs? For example I am not able to find the error that says 'Error, missing operator or `;'' in the following code.

While using a version of Maple on the inverse symbolic calculator I first described my idea for a new constant in 1999 and other people named it after me, calling it the MRB constant. While looking for an applied math purpose for the MRB constant =sum((-1)^k (k^(1/k)-1),k=1..infinity), I noticed that the absolute value of its summand is the interest rate to multiply an investment k times in k years=k^(1/k)-1. Any ideas on how this might be related to other subjects?

Download compre1try3.mw

I am facing the same problem with Maple 17. Which is also discussed here

https://www.mapleprimes.com/questions/222168-Maple-Not-Evaluating-Symbolic-Variables?reply=reply

But the link provided below is dead
https://www.maplesoft.com/support/faqs/detail.aspx?sid=34802

Can you recall how to solve it?  I have tried your solution below, but it did not solve it.  

"@peacess If the file isn't there you can just create a new file with a text editor (e.g. Notepad) and add the required option.
Or you can use the maplejava.l4j.ini file inside the .zip file I've attached:  maplejava.l4j.zip"

Thank you.  

This is a very general, basic question.  

When I supply an input is the calculuation/computation performed on my computer?  Is it uploaded to a Maple server for calculating? 

I am assuming it takes place on my computer but just wanted to double check.  

Also, is there a way to see the progress of a calculation?  If it is something that might take days or even weeks..

Hi there

I am trying to solve the ODE below

schechter_guo_v2.mw
 

Download schechter_guo_v2.mw

My questions are:

1. Why does the solution for the longer time span (t<10) looks different from the shorter time span (t<0.1)? I have read about stiff ODEs and probably this has something to do with it. I am trying to figure out what is going on with the solutions.

2. I tried dsolve with stiff methods (lsode and rosenbrock) and both gave me the same solutions as above. I have not tried the advance options yet. How do I set dsolve so that the solution for the longer span (t>10) looks similar to shorter span?

Many thanks for your answers/suggestions.

I am trying to use standard notation for machine constants such as Xd' and Xd'', the d being a subscript. The prims are interperted as differential operators. How can I disable the d/dx.   

I've followed all the recommendations, but I can't see the mistake yet...:

z := proc(n::integer)

local A,E,S,k,s1,s2;

if n = 0 then

matrix(2,1,[0,0]);

else if n = 1 then

matrix(2,1,[-2,epsilon^()+sqrt(epsilon^(2)+4)]);

else

A(n) := matrix([[1+epsilon^(2)-lambda^(n),epsilon^()],[epsilon^(), 1-lambda^(n)]]);

E := matrix(2,1,[epsilon^(2),epsilon^()]);

S := 0;

for k  from 1 by 1 to n-1 do

s1 := thisproc(n-k);

s1 := s1[1];

s2 := thisproc(k);

s2 := s2[1];

S := S+s1*s2;

end do;

A(n)^(-1)*E*S ;

end if;

end proc

I need this to do a Dynamical systems problem called Hénon map, which has by function formula:

f(x,y) = (x+epsilon*(y+epsilon*x*(1-x)), y+epsilon*x*(1-x))

so the problem consists in finding the expression of function P such that f(P(t)) = P(lambda*t), where lambda = 1+(epsilon/2)*(epsilon-sqrt(epsilon^2+4)) is one of the eigenvalues of the differential matrix of f valued on (0,0). In Maple, I've put z = (x,y) to let the problem be a vector problem. And as I made the calculations with the help of a LaTex-presentation PDF, I took the formula A(n)*z(n) = (epsilon^2;epsilon)*S, where s is the following recursive sum in the code. If I don't get the result, I won't be able to explain why Matlab plotting goes too far, even when n = 2!!! Bref, trying to put things much easier in a difficult problem, but Maple returns me the error like I did some mistake, and I tried to debug these code lines!!! Along the code, please note that lambda and epsilon are mere parametres, not local variables. If the error comes from there, please put epsilon = 0.2 and lambda as the formula just below the code.

Dear!

Hope everyone is fine. I want to write the values of "phi" with their line colors in legend or in title. I know how to make legends but the problem is here there are nine graphs and we need only three legends. Please fix my problem. I am waiting the positive response. Thanks in advance

Legend.mw

I want to solve this integer-linear programming problem. There are four variables (xp,xq,xifp,xifq)
Two variables are nonnegative and integer (xp,xq)

the other two variables are binary(xifp,xifq)
 

When executing this command, maple says that the problem appears to be unbounded

LPSolve(750*xp+250*xq-50000*xifq,maximize=true,
{20*xp+30*xq<=2600,
30*xp+20*xq<=1000,
20*xp+30*xq<=2000,
xq<=99999*xifq,
xq>=20*xifq,
xp<=99999*xifp,
xp>=30*xifp,
xp>=0,
xq>=0},
integervariables={xp,xq},
binaryvariables={xifp,xifq}
);

and gives this solution[0, [xifp = 0, xifq = 0, xp = 0, xq = 0]]

however if i set a range for the variables xp,xq from 0 to 99999 for example

LPSolve(750*xp+250*xq-50000*xifq,maximize=true,
{20*xp+30*xq<=2600,
30*xp+20*xq<=1000,
20*xp+30*xq<=2000,
xq<=99999*xifq,
xq>=20*xifq,
xp<=99999*xifp,
xp>=30*xifp,
xp>=0,
xq>=0},
integervariables={xp,xq},
binaryvariables={xifp,xifq},
xp=0..99999,
xq=0..99999
);
maple returns this solution 

[49950000, [xifp = 1, xifq = 1, xp = 50000, xq = 50000]]

but if xp=50000 and xq=50000 this doesnt satisfy the first constrain
because 20*xp+30*xq</=2600
why does maple gives this mistaken solution, how can i solve it ?
please help,thanks for reading