Hi ;

I need your help to write the system contains all these equation:



# system 1
u[0,0]:=(1/2)*(u[1,0]+u[0,1]);
u[0,N+1]:=(1/2)*(u[0,N]+u[1,N+1]);
u[N+1,N+1]:=(1/2)*(u[N+1,N]+u[N,N+1]);
u[N+1,0]:=(1/2)*(u[N,0]+u[N+1,1]);
# system 2
for j from 1 to N do
u[0, j] := (1/4)*(u[1,j]+u[1,j]+u[0, j-1]+u[0,j+1]-f[0,j]*h^2);
end do;
# System 3
for j from 1 to N do
u[N+1, j] := (1/4)*(u[N, j]+u[N-1,j]+u[N+1, j-1]+u[N+1, j+1]-f[N+1,j]*h^2);
end do;
system4
 eqs := [ seq(seq(Stencil[1](h,i,j,u,f),i=1..N),j=1..N)];

How can collect these system 1 system2, system3 ans system4 in a set with one name.


sys:=[eqs,system3,system2,system2]; ( sys: here contains all the equation).

Thanks you.

Hi,

When I run two times my code, the results change.

Have you any idea, why???

Hi:

i will calculation of value function in every step by 0.001(x=0,x=0.001,x=0.002,...x=10):

my function:

f(x)=x^3+2*x+1

my domain:

0<x<10

Hi , everyone who love Maple and dsolve command, 

my ODE is :

sys_ode := diff(d11(m), m) = -(3*sin(m)^2-1)*d31(m)/a^(3/2)+(-3*cos(m)*sin(m)/a^(3/2))*d41(m), diff(d21(m), m) = (-3*cos(m)*sin(m)/a^(3/2))*d31(m)-(3*cos(m)^2-1)*d41(m)/a^(3/2), diff(d31(m), m) = -a^(3/2)*d11(m), diff(d41(m), m) = -a^(3/2)*d21(m)

using " dsolve([sys_ode]) " command could get the solution easily, and the solution contains "I" (imaginary domain).

However, when we substitute the solution into the ODE "sys_ode", find not correct !

we use the following command to check the solution :

 simplify(  -diff(d11(m), m) -(3*sin(m)^2-1)*d31(m)/a^(3/2)+(-3*cos(m)*sin(m)/a^(3/2))*d41(m)  )

the upper expression is supposed to be zero, but not ! Is it a bug in Maple dsolve ?

Hi:

how can i convert one nonlinear second order ode to first order in maple?

How can I plot multiple numeric plots, such that numeric solutions belong to different differential equations?

For solving problem sets, I have a pdf template I created for myself that has a header with a blank for the class name, TA, professor, date, etc. In addition to this header, I had a margin on the left to scribble questions I had and to holepunch. 

I used to print out the template and write on the template and turn in that as my pset.

I am nowthinking of doing everything on the computer. Writing out all of the problem set on the computer. Combining stuff from maple, combining handwritten stuff from the computer using a digitizer. However I want to write it all on top of the my template that I created, which is a pdf file. I can turn the pdf into an image file if need be. 

What would be the easiest way to do what I want? To open a program that automatically sets that pdf as the template and easily lets me handwrite stuff I want and paste in maple code? 

Right now if I tried my idea, I would basically be constantly copying and pasting stuff from maple and my digitizer drawn pictures/equations into one file and it would be very clumsy.

Basically there are problems that I do partially on maple and I just want to unify all my work into one easy, printable file. 

I'm doing a pset in maple.

I paste in a block of text in maple. I put an asterik at front and end, and hit enter and it spits out an error. Why? I thought two *'s around it comment it out. 

I also can't see the file I uploaded while I preview my post. 

Hai everyone.

I try to double integrate this generalized extreme distribution.

q[p] := 6.256: h := .8; t[c] := .45: S[di] := 0: k[v] := .32639: mu[v] := -0.1786e-1: sigma[v] := 2.1694: k[t] := .36132: mu[t] := .63543: sigma[t] := 3.1183:

int(exp(-(1+k[v]*(v-mu[v])/sigma[v])^(-1/k[v]))*(1+k[v]*(v-mu[v])/sigma[v])^(-1-1/k[v])*exp(-(1+k[t]*(t-mu[t])/sigma[t])^(-1/k[t]))*(1+k[t]*(t-mu[t])/sigma[t])^(-1-1/k[t])/(sigma[v]*sigma[t]), [v = q[p]/(2*h*t)+q[p]*t[c]/(2*h)+S[di] .. infinity, t = 0 .. infinity]);

however, I got an error, as follow:

Error, (in assuming) when calling '`root/fraction`'. Received: 'numeric exception: overflow'

Any recomendations and tips to solve this integration? or this integration may cannot solve?

Thank you.

I have an expression like this:

Since it is linear I want Maple to rewrite it into this:

(with the benefit that Maple then can solve it at least up to a point). i have tried to conceive a rule to do that but got stuck relatively quickly. Does anybody have a way to do this (in some genrality)?

Thanks,

Mac Dude.

Hi, I want to define functions recursively... 

I don't know how to do it with the for loop in Maple.

I have a[0](t)=0, a[1](t)=t, and then some recursion connecting a[j+1](t) = f( a[j](t), a[j-1](t)) for some explicit function f. 

Then I want to plot the graph of a[N](t) as a function of t. 

Thanks!!

Hi, please a Need a help.
I have an error in my code: Error, (in collect) cannot collect 0
Here, is the code:
Question8X.mw

Many thinks.

Hello,

I am a student and using Maple to type homework assignments because of the math symbols available.  I was using Maple 17 but upgraded to 18, and its not as easy to use as 17.  For right now I am using it in text mode, because that is what I need.  But I can't figure out an easy way to do subscripts and superscripts in text mode.  Also, the "element symbol," where is it?  I feel like a lot of stuff is missing.  For instance, the arrows, the sideways triangle, lots of symbols I used before the upgrade I cant find.  Can someone help please???

After using Simplify the indices are are arranged in the tensor.  I am using the April 14th update from the Physics R&D page.

Download Vacuum_Solutions_(Kerr-Schild)_3.mw

Here is a problem I have with the Nabla operator:

I am working on a demonstration involving Maxwell's equations:

restart:with(Physics[Vectors]);
Setup(mathematicalnotation = true);
# Maxwell's eqn
M4 := `&x`(Nabla, B1_(x, y, z, t)) = mu*epsilon*(diff(E1_(x, y, z, t), t));

eval(subs(B1_(x,y,z,t)=Bxx(x,y,z,t)*_i+Bzz(x,y,z,t)*_k,M4)); # transverse magnetic field, no longitudinal (j) component

# Ok, this one is as expected.

eval(subs(B1_(x,y,z,t)=Bxx(x,y,z,t)*_i+Bzz(x,y,z,t)*_k,M4)) assuming real;

# Hmm... why is this zero?

eval assuming real seems to make them all zero. In this little example, Bxx and Bzz are just arbitrary functions and therefore the result cannot be zero in general. The bother here is that I later use a parametrization of the field (the Bxx and Bzz) which in fact does make curl(B) = 0. I wanted Maple to demonstrate that the parametrization does that, but it appears i can make the result zero for any B-field, which sort-of defeats the purpose. If I don't assume real, with the other parametrization Maple isn't getting anywhere...

So, how can I get correct results while declaring variables to be real when they are... ?

Thanks,

M.D.

Maxwell_test.mw