Hi,

While using pdsolve for a coupled system of pdes, the maple results doen't match with the desired ones.

Here is the system

restart:

Eq1:=diff(f(eta,tau),eta$3)+(f(eta,tau)+h(eta,tau))*diff(f(eta,tau),eta$2)-diff(f(eta,tau),eta$1)^2

+(1+epsilon*cos(Pi*tau))*theta(eta,tau)=Omega*diff(f(eta,tau),tau);

Eq2:=diff(h(eta,tau),eta$3)+(f(eta,tau)+h(eta,tau))*diff(h(eta,tau),eta$2)-diff(h(eta,tau),eta$1)^2

+c*(1+epsilon*cos(Pi*tau...

Why can't Maple solve this integral equation using intsolve? May be my error entering it?

sys:= diff(y(t),t)=2-t^2/2 - 1/4 * int(y(t1),t1=0..t);
intsolve(sys,y(t));

Error, (in unknown) invalid input: diff received 0, which is not valid for its 2nd argument

I solve it by hand, and wanted to verify the solution. I get y(t)=C* sin(t/2) -4*t and C can be found to be 12
 

Hello,

I just installed maple 15 as well as the latest update. However, when I was trying to plot, it gives me this:

Which had never happened before I reinstall my operation system.

Could anyone help me please? Thanks a lot!

I have a variable with some assumptions: assume(0<=W<=1).

Now, when I make a list and sort it, everything goes fine:

k := [W, (1/3)*W, (1/3)*W, (1/3)*W]:
sort(k, (a,b)->is(a>b))

I get [(1/3)W, (1/3)W, (1/3)W, W] as expected.

Now I try this:

k:= Vector[column]([W, (1/3)*W, (1/3)*W, (1/3)*W]) 
sort(k, (a,b)->is(a>b))

And Maple gets stuck on this computation. I have tried on both Windows and Linux, on several different computers.

ASK.zip

Hi all,

In short, I want to use

'ss' expression(1)

to simplify

'kappa' expression (2).

At the moment, I can only archieve it through solving for each variable and get to expression (5).

simplify using siderules failes in this case. Is there another way to do it?

Thanks,

Casper

Hi folks, the package PDEtools has a nice command declare that allow us to display PDEs using jet notation: say f[x]-g[y] instead of diff(f(x,y),x)-diff(g(x,y),y) but when I try to export it to LaTeX or just trying to copy and paste the display in a text file, I always get the long expression. If I try to copy as MathML I got junk... Any ideas on how to copy an expression displayed in jet notation to a text document?

Hello, I would like to use the LeastSquares subpackage in the LinearAlgebra package in order to solve the following problem:

Set of data: (1.0,2.33),(2.0,0.0626),(3.0,-2.16),(4.0,-2.45),(5.0,-0.357),(6.0,2.21),(7.0,2.75),(8.0,0.636),(9.0,-2.45).

I am trying to put the above data in the curve y=a+b*cos(x)+c*sin(x)+d*cos(2x)+e*sin(2x).

My attempt to solve this:

restart;

with(LinearAlgebra);

Find the eigenvalues and eigenvecotrs for A=[2 0.37 0]

                                                                [0  1.1 -4.29]

                                               ...

Find the quadratic polynomial which interpolates (2,0), (6,1), (8,0). Start by setting f(x)=ax^2+bx+c, for example, and the unknowns as a,b,c.

Hello,

I have the following system of equations to solve which is quite big.. Does anyone know how I can solve it faster or in a more simple way?

Thanks 

solve({(-(1/((0.002+0.001)^2+(0.001+1*(e+p))*(0.001+1*(j+p))))*((0.002+0.001)*sin(-0.39)-(0.001+1*(e+p))*cos(-0.39)*(e*(-m+(0.68/d)+(0.599/g))+j*m)-(1/((0.002+0.001)^2+(0.001+1*(e+p))*(0.001+1*(j+p))))*((0.001+1*(j+p))*sin(-0.39)-(0.002+0.001)*cos(-0.39))*(j*(-n+(0/i)+(-0.73/l))+e*n...

eqt := y^5+y^4 + -0.5109*y^3 + -0.0595*y^2 + 0.0000-(-3.1086e-015*u^4 + u^3 + -0.5109*u^2 + -0.0595*u) = 0;

solve({eqt, y=m*t+c, u=n*t+d}, {y, u}, 'parametric');

solve({y^5+y^4 + -0.5109*y^3 + -0.0595*y^2 + 0.0000-(-3.1086e-015*u^4 + u^3 + -0.5109*u^2 + -0.0595*u) = 0, u=t}, [x,y]);

solve(eqt, [y(t), u(t)])

algcurves[parametrization](eqt, y, u, t);

all trials i failed

Hi. I have a question it goes.

Find the equation f(x) which satisfies the following conditions. f'(x)= 1/(1+cot(x)) and f(pi/4)=1.

So I enter the following in Maple and this is what I end up with.

http://s5.postimg.org/eriq99rs7/Maple.jpg

This should work as far as I can tell. The final diff command should return the original f'(x), but it doesn't. Can anyone tell me why?

I have used this exact method before on similair problems and it...

Hi,

I have a linear problem A*X = B, with dimensions of A approximately 500*1300, and B is a vector with only one nonzero coordinate.

I feed it to LinearSolve, and there are a *lot* of solutions - presented as one vector with linear polynomial coordinates.

How can I get only one (hopefully with as many zeros as possible) ?

Thank you in advance.

NoThik

Hi,

Does anyone know why I cannot solve the following system of equations?

solve({(-(0.1e-2+e+p)*j*(e*(-m+.68/d+.599/g)+j*m)/(((0.2e-2+0.1e-2)^2+(0.1e-2+e+p)*(0.1e-2+j+p))*i)+(0.2e-2+0.1e-2)*j*(j*(-n+0*(1/i)-.73/l)+e*n)/(((0.2e-2+0.1e-2)^2+(0.1e-2+e+p)*(0.1e-2+j+p))*i)-j*m/i)/(2*10) = -0.3e-2, (-(0.1e-2+e+p)*j*(e*(-m+.68/d+.599/g)+j*m)/(((0.2e-2+0.1e-2)^2+(0.1e-2+e+p)*(0.1e-2+j+p))*l)+(0.2e-2+0.1e-2)*j*(j*(-n+0*(1/i...

HI,

I have a system of ODEs like