Unanswered Questions

This page lists MaplePrimes questions that have not yet received an answer

Dear all:

hello everybody;

I need your help to solve the system f(x,y)=0, and g(x,y)=0, such that there some parameter in the system, also all the parameter are positive and also our unkowns  x and y are also positive.

I try to write this code. I feel that under some condition we can have four solution or three or two. I need your help. Many thinks.

 

Systemsolve.mw

follow Computing non-commutative Groebner bases and Groebner bases for modules

using LeadingMonomials(f, lexdeg([s],[x,y]));

f:=[y^2+2*x^2*y, y^2];
f1:=[x+y^2,x];
f2:=[x,y];

g:=[f1,f2];

 

LeadingMonomial(g[1], lexdeg([s],[x,y]));
LeadingMonomial(g[2], lexdeg([s],[x,y]));
LeadingMonomial(g[1], lexdeg([s],[y,x]));
LeadingMonomial(g[2], lexdeg([s],[y,x]));

 

no result is (0,y^2)

where is wrong?

 

Determine the exact solution to the initial value problem

 

y'(x)=   (y(x)(20-y(x)))/80 , y(0)=1

                

 Compute a polynomial approximation to y(x). Plot this polynomial approximation together with y(x) on the same axes for x∈[0,20]. Choose different colours and linestyles for each curve.

 

Investigate whether or not it is possible to choose Order to be large enough to ensure that the plots of the polynomial approximation and y(x) are indistinguishable over the [0,20] interval? If this is possible, determine the minimum value of Order required. If you think that it is not possible, explain why not.

 

 

I tried

des := diff(y(x), x) = (1/80)*(y(x))(20-y(x))

and

ics := y(0) = 1

then i type

soln := dsolve({des, ics}, {y(x)})

came up with

y(x) = RootOf(x-(Int(80/_a(20-_a), _a = _b .. _Z))+80*(Int(1/_a(20-_a), _a = _b .. 1)))

 

then i tried 

Y := convert(rhs(soln), polynom)

it gives me the same thing

 

i put

PY := plot(y, x = 0 .. 20)

then it's error...

 

what should I do next?

 

I have a three paramter ode problem that involves three tanks with given initial concentrations.  Overtime the concentration equalizes but one of the steps is to determine all bifurcation values.  Not sure how to continue with this number of variables.

 This is our given system with initial conditions

sys_ode := diff(x(t),t) = (-r*x(t))/100+0+(r*z(t))/50, 
> diff(y(t),t) = (r*x(t))/100+(-r*y(t))/25+0,
> diff(z(t),t) = 0+(r*y(t))/25+(-r*z(t))/50;
> x0:=0; y0 := 200; z0:=0;

Hello,

I would like to copy/ paste my maplesim model in microsoft visio.

The idea is to create a vectorial illustration for presentation.

I manage to do this with simulink but not with Maplesim.

Apparently, when I go in visio, there is no possibility to copy like a metafile.

Is there a possibility to copy the object of a Maplesim model in a software like visio or illustrator so as to be able to create vectorial illustration for presentation ?

Thank you for your help.

I have two Reissner Nordstrom black holes that are near extreme. How do I show they move? 

When i copy expression and past it in word, i can change the size of the picture whitout loosing the detials.

How can i export the expression to a file, such that when i will open it in word i could change the size without loosing details? much thnks :)

Dear Maple users,

My problem is as follows:

I have a factor base [2,3,5,7,11,33,34,35,36,37,38,39,40]

The numbers from 2 till 11 are primes, the rest is not. 

Then I have to factor (H+c1)(H+c2) in numbers of the factor base , where c1 and c2 go from 1 to some pre-defined limit. H=32 in my case.
And then I have to put the powers of the numbers of the factor base in a matrix. For example: (H+1)(H+1)=33² but also (H+1)(H+1)=3²*11².

That will become in matrix form [0 , 2, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0 ] but also (!) [0 , 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0 ].

This is not what I want! I want no double representations....

What I want is that (H+c1)(H+c2) should be represented in primes in the matrix if possible and else just represented as the other numbers.

 

hope you guys can help me!

Surely this is a bug.

> 0^0;
                 1 
> sum( 0^m, m=0..infinity );
                 0

So I'm having trouble using maple to find the relationship (formula) between two sets of data

 

I have time and current as t1, t2, t3...so on, and current.

 

Is there anyway to use maple to find it?

st6.mw,st7.mwI want to obtain the analytical solution for this PDE by maple   diff(T(x, y, z), x, x)+diff(T(x, y, z), y, y)+diff(T(x, y, z), z, z)+A*exp(-8*x^2/a^2)*cosh(alpha*((1/2)*b+y)) = 0    . But I can not do it. Please help me

((d^2)T/dx^2)+ ((d^2)T/dy^2)+ ((d^2)T/dz^2)=-A*Q(x,y,z)

Where   0 <x<a ,  0 <y<b  ,  0 <z<l

With the boundary conditions:

(dT(0,y,z)/dx)=n-T(0,y,z)    (dT(a,y,z)/dx)=n-T(a,y,z)   (dT(x,0,z)/dy)=n-T(x,0,z)

(dT(x,b,z)/dy)=n-T(x,b,z)     (dT(x,y,0)/dz)=n-T(x,y,0)    (dT(x,y,l)/dz)=n-T(x,y,l)

where n is constant and A is set of parameters.

I am attempting to have Maple pull out the Eurocup qualifying scores from here http://www.uefa.com/uefaeuro/qualifiers/season=2016/matches/all/index.html

It doesn't seem to grab the full page.  Doing a search on Portugal only finds the one match against Albania.  Similarily a search on England only finds the match against Switzerland.  It seems to only find one instance and I'm not sure why it doesn't Get the full page. 

Any ideas?

I'm using the command

HTTP[Get]("http://www.uefa.com/uefaeuro/qualifiers/season=2016/matches/all/index.html")

Hey, how is can i see all the steps in maple? I would specially like to know it for differential equations.

For example we could use this one:

dl := 3*(diff(y(t), t, t))+6*(diff(y(t), t))+4*y(t) = 0 

I'd like to implement this in Maple, but being a newbie having hard time getting the syntax right:



This is what I tried:

a:='a';
f:= i->product( `if`(evalb(i<>j),(a-z(j))/(z(i)-z(j)),NULL),j=1..3);

but it is not skipping the i=j case, since when I call it with f(1) I get division by zero.

f(1);
Error, (in product) numeric exception: division by zero

Tried also

f:= i->product(`if`(evalb(not(i=j)),(a-z(j))/(z(i)-z(j)),NULL),j=1..3);
and few other things. I think the reason it fails is deeper than my level of Maple undertstanding.

How would you do this in Maple?

I came across this website www.fuelsonline.ca that has their price for furnace oil and Propane.  I thought it would be fairly easy using HTTP[Get] to fish out the prices, but it turns out those values on the page are images in of course a format (PNG) that cannot be read by Maple.  I don't know where that web page is pulling the prices from but it looks like web surgery with Maple will be unable to (at least not easily) wean the numbers out. 

If anyone has any ideas I would be interested in knowing.

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