Hi,

I have a system of diff equations (see below). I am trying to obtain analytical solution. when I assume that z=wN, I receive such solution. Do anybody have idea if I know that z>wN, does this system has an analytical solution?

diff(K(t), t) = -(1/2)*(Q(t)^2*alpha^2*eta*upsilon-2*eta*alpha*(N*upsilon*w*C[max]-z*alpha*K(t))*Q(t)+N*w*(-2*C[max]*z*eta*alpha*K(t)+upsilon*((-N*w+z)*alpha+N*C[max]^2*w*eta)))*K(t)/((C[max]*w*N-alpha*Q(t))*upsilon*N*w)

diff(Q(t), t) = (1/2)*(-z*(Q(t)^2*alpha^2*eta-2*N*Q(t)*alpha*eta*w*C[max]+w*(w*(eta*C[max]^2-alpha)*N+z*alpha)*N)*K(t)-2*N*upsilon*w*(N*w-z)*(C[max]*w*N-alpha*Q(t)))/((C[max]*w*N-alpha*Q(t))*upsilon*N*w)

K(0) = K0, Q(0) = Q0

Thanks,

Dmitry

Hi all,

I would like to set equal to zero some monomials in a polynomial. In particular those monomials in which an unknown has a certain degree. 

For example for the polynomial

poly := x^2*y+x*y*z+x*z

i would like to set equal to zero the monomials in which x has degree 1, that is x*y and x*z.

Is there a way to do it?

Thanks in advance
Manuele 

http://www.math.uni-frankfurt.de/~numerik/maplestoch/

read "D:/diffalg03/stochastic9";
Sigma := `<,>`(`<|>`(1.0, .5), `<|>`(.5, 1.0));
V := WienerProcess(Sigma);
Z := t -> exp(a*t+b*V(t)[1]+c*V(t)[2]);
drift1 := simplify(Drift(Z(t))/Z(t));
diffusion1 := simplify(Diffusion(Z(t))/Z(t));
with(stochastic);
linearsde(drift1, diffusion1[1][1]);
Euler(x[1],drift1,diffusion1[1][1]);

1.what are a, b, and c?

2. how to convert SDE for monte carlo for this ito formula?

3. how to convert to euler scheme with this ito formula

Hello fellow maple users,im new to the software,im trying to solve a differential system but it dosent work

This is the system :

DE1 := diff(Y(t), t) = 5*Y(t)*ln(b(t)/Y(t))-5*Y(t)

DE2 := diff(b(t), t) = 5*b(t)*Y(t)^(3/2)-5*Y(t)

Thank you for your help !

I have a function f(X,Y) and I create a random sequence of input values for X and Y.

I now want to create a 2D scatter plot with X and Y on the axis, on the graph I want each point (X,Y) to be color coded according to the value of f(X,Y).  For example, 0<f<1 Red, 1<f<2 Blue, 2<f<3 Green.

Does anyone know how I could do this? 

sin(xy) = x + y

subs( y(x)=y, solve( diff(subs( y=y(x), (1) ),x), diff(y(x),x) ) );

-1

subs( x(xy)=x, solve( diff(subs( x=x(xy), (1) ),xy), diff(x(xy),xy) ) );

cos(xy)

I can not get this answer to come out correctly when using this software please help. the correct answer in the back of the book is 

1- y cos(xy)

--------------

x cos(xy) - 1

And is there a way that this program can tutor me on how to get this answer intead of spitting out the answer 

the diff tutor only allows for a one sided equation to be entered.

Hello,

I wanted to ask whether it's possible to use the taylor command together with vectors from the physics package, maybe I am just doing something wrong here. I tried the following:

and get an error message that diff cannot handle vectors. Of course I could do the expansion by hand an enter the result in Maple but I think it would be a very nice feature because an expansion of vector fields which vary in space and time is such a common problem e.g. in classical electrodynamics. I think of an expansion with non-projected vectors such as

+ higher order terms.

Thanks a lot!

Peter

Hi. I want to differentiate the following expression using "Diff", not "diff". but I want to apply "Diff" to differentiate each separate term based on the chain rule. How can I do that? Does "Diff" apply chain rule for differentiation?

I wish to substitute Re=W[0]/V[0] in the expression V[0]/W[0] * diff(u(t),t). I tried using the subs command but it didn't work. Any help would be appreciated !

When greek symbols are used in code edit region (by copying from worksheet 2d math mode), they used to get exported properly to PDF but the only issue was large code edit region used to get cut off. But now with this new 18.01 update, code edit region is not cut off but greek symbol inside code edit region are not appearing in PDF export instead just pink boxes. Has anyone else also encountered this issue and suggest a resolution.

Hi Everyone,

    I just upgraded a Linux 64-bit computer from Maple 17 to Maple 18.01.  Code that worked on Maple 17 no longer works on Maple 18.01.  The code uses BLAS matrix operations in in the LinearAlgebra package.  When the first such operation is called, I obtain the following fatal error:

MKL FATAL ERROR on loading the function mkl_blas_avx_xdcopy.

Maple 18.01 is unable to load any of the MKL routines even though the MKL shared libraries are in the Linux bin directory.  If I load my own MKL library (provided by Intel), Maple 18 will run these operatrions, but they ultimately lose precision which causes the program (which works fine in 17) to crash.  Any ideas about how to activate the version of MKL provided by Maple?  Will this version not loose floating-point precision?  Any help is greatly appreciated.

Best wishes.

David

University of Chicago

mode_shapes_and_critical_load(changed_model).mw

This is my code for finding mode shapes and critical load for a bimaterial strut under buckling. 

Although everything else is working fine but I have a problem while solving for critical load.

h_new := convert(series(h, P, 3), polynom):

h_new := convert(series(h, P, 3), polynom):

without converting to polynomial, the code is unable to solve for P. Even on conversion, for differnet S values, I need to change the truncation order of conversion (like for S=0.5, it would work with 3 but for other S values I have to change truncation (convert(series(h, P, 6), polynom)), which also causes the number of solutions of equation to change which causes problem with plotting of graphs of critical load that I need (basically I need lowest two plots), thereby restricts me from automating the code with a for loop. I need to test it for various S values and then later in code I need to put teh critical load back and check mode shapes for different a values.

Is there a better way to solve two variable equation to get one variable in terms of another(the equation is quite complicated, contains trigonometric expressions). 

and also if I try to automate the analysis for different S and a values, teh process needs to put teh value back in P which changes everything and teh next time loop operates it just ruins everything. Also there are varied number of solutions of P_crit for differnet S values which makes it difficult to store those solutions during automation?

hello

please compare result of DirectSearch and implicitplot. which of them is correct??

please help me.please......

resul.mw

Hi,

  I have an expression as p in the following. I would like to extract the coeffient with x^n*y^m and x^(n+2)*y^(m+2), however, coeff comand does not work...

***

p:=3*x^n*y^m+4*x^(n+2)*y^(m+2)+k*x^(n+2)*y^(m+2);
coeff(p,x,n);

***  

gives me

***

n m (n + 2) (m + 2) (n + 2) (m + 2)
3 x y + 4 x y + k x y
/ n m (n + 2) (m + 2) (n + 2) (m + 2) \
coeff\3 x y + 4 x y + k x y , x, n/

***

What is the correct command to get the coefficients? Thank you very much

Hi,

I would like to format the solution given by maple.
I have the answer given by a paper and I would like to reproduce the same formula.

I have the expression :

(a1/2+a2/2)*ln(a1/2+a2/2+sqrt((a1/2+a2/2)^2+(b1/2-b2/2)^2+d^2))+(a1/2-a2/)*ln(a1/2-a2/2+sqrt((a1/2-a2/2)^2+(b1/2-b2/2)^2+d^2))

I would like to assume deltaa = a1-a2 and sigmaa = a1+a2.

The issue is that algsubs(deltaa = a1-a2, expr), my a1+a2 is replaced by deltaa+2*a2 and same for algsubs(sigmaa = a1+a2, expr), so i can't have sigmaa*ln(...) + deltaa*ln(...).

And all my squares are developed, for example I have : sqrt(1/4*a1^2+1/4*a2^2+1/2*a1*a2+...)

I can't put them in canonical form (1/2*a1+1/2*a2)^2 to get (1/2*sigmaa)^2.

Sorry for my english,
If you know how to do, i would be really grateful !

Mathieu