I consider a PDE system (?pdsolve,numeric)

PDE := {diff(u(x,t),t)=-1/20*diff(v(x,t),x,x),
diff(v(x,t),t)=diff(u(x,t),x,x)}:

IBC := {u(x,0)=sin(Pi*x), u(0,t)=0, u(1,t)=0,
v(x,0)=1-x, v(0,t)=1, v(1,t)=0}:

pds := pdsolve(PDE, IBC, numeric, spacestep=1/50);

Suppose, I need to use the data diff(u(x,t),x,x)  or diff(v(x,t),x,x) at x=0.

Hi, i wouls lij=ke to see the consequences of damping on coupled oscillators.

I encounter no problem with

restart; m := 1; k1 := 1; k2 := 1; lambda := 0;

eq1 := m*diff(x1(t), `$`(t, 2)) = -k1*x1(t)+k2*(x2(t)-x1(t))-lambda*diff(x1(t), t);

eq2 := m*diff(x2(t), `$`(t, 2)) = -k2*(x2(t)-x1(t)); ICS := x1(0) = 1, x2(0) = 0, (D(x1))(0) = 0, (D(x2))(0) = 0; sol2 := dsolve({ICS, eq1, eq2}, {x1(t), x2(t)});

plot(eval(x2(t), sol2), t = 0 .. 20);

Hi,

Really, can't understand why there's a problem in the line desolve

restart;

eq1 := m*(diff(x1(t), t, t))-f = 0;

f := -k*x1(t)+k*(x2(t)-x1(t))-lambda*(diff(x1(t), t)) ;

g := -k*(x2(t)-x1(t)); eq2 := m*(diff(x2(t), t, t))-g = 0;

fcns := {x1(t), x2(t)};

ICS := {x1(0) = 1, x2(0) = 0, D(x1)(0) = 0, D(x2)(0) = 0};

sys := {eq1, eq2}; m := 1; k := 1; lambda := 1; sysdiff := sys union ICS;

hi dear

i am a student of m.phil in maths.

i am doing my research in numerical solution of fractional derivatives but

i am facing a little problem in writing the code for fractional derivatives by hpm

in mathematica software if you are having any code kindly sent it to me

thanks

Hi

1st, sorry, i did'nt find the "question" forum so i post here

2nd, difficulties in converting the maple code in text here

3rd : my problem of the day

retart :eq1 := m*(diff(x1(t), t, t))-f = 0; f := -k*x1(t)+k2*(x2(t)-x1(t))-lambda*(diff(x1(t), t));

eq2 := m*(diff(x1(t), t, t))-g = 0; g := -k2*(x2(t)-x1(t)); fcns := x1(t), x2(t);

ICS := {x1(0) = 1, x2(0) = 0, (D(x1))(0) = 0, (D(x2))(0) = 0};

sys := {eq1, eq2};...

I want to print     a_n   is  in  S .

Here are what I tried.

So here is what I need to do within Maple.  I have to define a piecewise function and then determine left and right hand derivatives at a certain x value.  Then determine the whole derivative and graph both parts.  I am just pretty new to Maple so it is still fairly confusing and I cannot determine the exact commands that I need.

hi,look at that. I obtain a curve. But when i do it again

I have a second order ODE, eq, that depends on a paramter p. Certain events take place when solving the ODE and I would like to study those events as a function of p. Here is a toy version of the command that yeilds the information I need.

>dsolve({eq, f(1)=1,D(f)(1)=0},f(t), numeric, events=[  [ [f(t)-Pi,t>0],halt   ]  ,

 [  [f(t) =-1, t>0],halt]  ])(15);

When f hits  -1 or Pi the solution stops and gives...

Hi

I'm trying to make a phase portrait for coupled oscillators. No problem for the following lines

Dear All:

  I met an strange problem when using fsolve() function in maple. the following is my system equations, ILr0,Vcr0,M,T1 is the values i need to solved by maple . 

   ILr2+ILr0=0,Vcr0+Vcr2=0,ILr1=ILm1,Iout*RL=Vout   (1)  where

   ILr2--> ILr0*f1(T1)+Vcr0*f2(T1)+M*f3(T1);

   Vcr2--> ILr0*g1(T1)+Vcr0*g2(T1)+M*g3(T1);

   ILr1,ILm1-->  ILr0*h1(T1)+Vcr0*h2(T1)+M*h3(T1);

Hello,

I've got a recurrence equation system like:

fn:={f(x)=sum(f(k)*f(x-k-1),k=0..x-1),f(0)=1}

appearently

rsolve(fn,f(k))

doesn't work.

Is there a way to solve this with maple?

Actually I also would like to solve this step by step, by hand. Could you refer me to something that could help me, solve my problem?

Hi

I am getting the floating point error during the job running. it happens instantly for the first fopen command and after some calculations it happens for the second fopen command also.

I would be appreciated if you could help  me in this regards,

Thanks.

here is the code:

> restart;
> w := 0.5695419e-1; T := evalf(2*Pi/w); Cl := 137;
> A := -(int(sin(w*t), t));
> P0 := -subs(t = t1, A)/Cl;
> mrdot0 := int(P0+A/Cl, t = t1 .. t2);

So I am fairly new to Maple and cannot figure this out.

I had to define and equation and then differentiate it and then evaluate this derivative at 2 and now I need to solve the derivative where the derivative=0 for x.  I can do this real easy on paper but I cannot figure out the right set of commands to do so in Maple.  Thank you

Is there a command the takes (A*B)^a and returns A^a*B^a ?

I tried expand and  simplify and also used assuming a>1 but without luck here...

I know this is very basic but I have monster product expressions that I need to be able to raise every term inside the parenthesis by the power so I can isolate some terms of interest.