I am now working on differential equations like the following, and wonder how I can deal with diff(C(x,t),x).  In particular, I would like to know the values of diff(C(x,t),x) at specific sets of (x, t).  I also would like to know how to integrate diff(C(x,t),x) for a time period (at x = 0.5L or x = L).

restart;

C0 := 10;

K  := 3.0e6;

d  := 5.0E-14;

hm := 5.0E-4;

L  := 0.001;

DE1 := diff(C(x, t), t) = d*diff(C(x,t), x, x);

IC := C(x, 0) = piecewise(x < 0, 0, 0 <=x <= L, C0, L < x, 0);

BC1 := D[1](C)(0, t) = 0;

BC2 := -d*D[1](C)(L, t) = hm * C(L, t) / K;

pds:=pdsolve(DE1, {IC, BC1, BC2}, type=numeric, spacestep=L/10000, timestep=10000);

T := 60*60*24*100;

pds:-plot(t=T, x=0..L);

#I tried the following, but these seem to always return zero (while the plot suggests some negative value of diff(C(x, t), x));

v1 := pds:-value(diff(C(x, t), x));

v1(L, T);

v2 := pds:-value(int(diff(C(x, t), x), t = 0 .. T));

v2(L, 0);

Hello all,

I really don't know what is going on with my code but I think I can use some help. I'm new to Maple and to parallel programmimg. What I would to understand is why the following code is simply not working.

evList := seq(seq([i,j],j=i..6),i=1..6):
M := Matrix(6,shape=symmetric):
integMult := proc(kIni::integer, kFin::integer)
  local i, j, k, l, kk;
  global evList, M;
  for kk from kIni to kFin do
     i := evList[kk][1]:
     j := evList[kk][2]:
     M[i,j] := Matrix(3*n,(k,l)->evalf(int(expand(N[i][k]*N[j][l]),x[1]=0..a,x[2]=0..b)));
  od:
end proc:
Start(null, Task=[integMult,1,10],Task=[integMult,11,21]);

When I consider one single Thread (i.e. 1 to 21), it works like a charm. But the code written above gives me a kernel lost. I don't know if it is the shared variable "M" (matrices of matrices) or if it is the shared parameter (vector of vectors) , or both. But I've tested duplicating both and nothing different happens.

Can anyone help me?

hi 

i have an equation like thes:

i want to classify Coefficients of F & H like this:

anybody can help me to how i do it?

thank you.

I can solve three equations for x like this

restart:
x := y/p:
z := x*a+y*(1-b):
x := 100*z/(p*r+r);

                            /y a            \
                        100 |--- + y (1 - b)|
                            \ p             /
                   x := ---------------------
                              p r + r      

However, I dont like the fact that x is a function of y. I just want x to be a function of a, b, p and r. So I try to expreses the equations as follows:

restart;
y := p*x;
x := 100*z/(p*r+r);
z := x*a+y*(1-b);
solve(z, x);

Error, recursive assignment
Warning, solving for expressions other than names or functions is not recommended.

Any idea how I can get an equation for x that only depend on a, b, p and r? 
 

Hi there,

I was asked to compute the inverse laplace transform of 
1/s^2 + (e^s - 2)/(s*(e^s-1))

I've tried to evaluate it using online calculators like wolframalpha.However,none of them was able to give an answer.

So,this is what I've got from Maple:

I was wondering if it is correct.The graph doesn't look too bad but I've no idea what 1+frac(t) means.Some help would be greatly appreciated,thanks!

p.s.I've loaded the with(inttrans) package

This fails (the code computes the quotient group directly from the definition):

with(GroupTheory):

Qgr := (sgr, gr) -> CustomGroup(LeftCosets(sgr, gr),
  `.` = ((a, b) -> LeftCoset(Representative(a) . Representative(b), sgr)),
  `/` = ((a) -> LeftCoset(Representative(a)^(-1), sgr)),
  `=` = ((a, b) -> Elements(a) = Elements(b)));

gr := QuaternionGroup();
Generators(gr);
                [(1, 2, 3, 4)(5, 6, 8, 7), (1, 5, 3, 8)(2, 7, 4, 6)]

qgr := Qgr(Subgroup({Generators(gr)[1]^2}, gr), gr);
                  qgr := ` < a custom group with 4 generators > `

AreIsomorphic(qgr, DirectProduct(CyclicGroup(2), CyclicGroup(2)));
Error, (in =) invalid keyword expression

If I rename the parameters in the definition of Qgr, e.g., change the last line to

`=` = ((aa, bb) -> Elements(aa) = Elements(bb))

then everything works, AreIsomorphic gives true.

Download velocity_tehta1.mwvelocity_tehta1.mw

Hello,

I am facing a problem when trying to simplify those kind of equation: 

((((((((((((((OD &and (NPi &or NEXTotp)) &and &not ((((((((POinoBlaze &and &not (OD &and ((POLYGi1 &and POBIASPdrawing2) &or  (POLYGi1 &and POBIASMdrawing2)))) &or (OD &and (spolyp2 &or spolym2))) &and &not (OD &and ((POLYGi2 &and POBIASPdrawing4) &or (POLYGi2 &and POBIASMdrawing4)))) &or (OD &and (spolyp4 &or spolym4))) &and &not (OD &and ((POLYGi3 &and POBIASPdrawing6) &or (POLYGi3 &and POBIASMdrawing6)))) &or (OD &and (spolyp6 &or spolym6))) &and &not BLACKBOXall) &and &not POLYACTsign)) &and (((BULK &and &not (SUBS1 &and &not MSUB0)) &and &not (NWELi &and &not MKRMSKREG)) &and &not PWbki)) &and &not ((NACTALL0 &and &not  NWRNW) &and &not  PWELL1)) &and &not OD225dg) &and &not OD218dg)  &and &not ((VNPNMSIPW &and &not EMPTY) &or (VNPNMSIPW25 &and &not EMPTY))) &and &not RPOi) &and &not ((NACTALL0 &and PWELL1)  &and  POi)) &and &not (((OD &and (PPi &and &not (SEALRINGi  &and &not PMDMY))) &and &not POi) &and PWELL1)) &and &not VTHNi) &and &not VTLNi) &and ((DCOng &or DCOmsk) &or DCOdg)) &and &not MKRHPA) &and &not EMPTY

When i try to simplify the previous equation by using this methode:

with(Logic);
BooleanSimplify(Equation);

Maple runs in loop and i'm just getting those kind of replys :

    |\^/|     Maple 2016 (X86 64 LINUX)
._|\|   |/|_. Copyright (c) Maplesoft, a division of Waterloo Maple Inc. 2016
 \  MAPLE  /  All rights reserved. Maple is a trademark of
 <____ ____>  Waterloo Maple Inc.
      |       Type ? for help.
> with(Logic);
        [&and, &iff, &implies, &nand, &nor, &not, &or, &xor, BooleanGraph, BooleanSimplify, Canonicalize, Complement, Contradiction, Dual, Environment, Equivalent, Export, Implies, Import, Normalize, Random, Satisfiable, Satisfy, Tautology, TruthTable, Tseitin]

> BooleanSimplify(((((((((((((((OD &and (NPi &or NEXTotp)) &and &not ((((((((POinoBlaze &and &not (OD &and ((POLYGi1 &and POBIASPdrawing\
> 2) &or  (POLYGi1 &and POBIASMdrawing2)))) &or (OD &and (spolyp2 &or spolym2))) &and &not (OD &and ((POLYGi2 &and POBIASPdrawing4) &or \
> (POLYGi2 &and POBIASMdrawing4)))) &or (OD &and (spolyp4 &or spolym4))) &and &not (OD &and ((POLYGi3 &and POBIASPdrawing6) &or (POLYGi3\
>  &and POBIASMdrawing6)))) &or (OD &and (spolyp6 &or spolym6))) &and &not BLACKBOXall) &and &not POLYACTsign)) &and (((BULK &and &not (\
> SUBS1 &and &not MSUB0)) &and &not (NWELi &and &not MKRMSKREG)) &and &not PWbki)) &and &not ((NACTALL0 &and &not  NWRNW) &and &not  PWE\
> LL1)) &and &not OD225dg) &and &not OD218dg)  &and &not ((VNPNMSIPW &and &not EMPTY) &or (VNPNMSIPW25 &and &not EMPTY))) &and &not RPOi\
> ) &and &not ((NACTALL0 &and PWELL1)  &and  POi)) &and &not (((OD &and (PPi &and &not (SEALRINGi  &and &not PMDMY))) &and &not POi) &and PWELL1)) &and &not VTHNi) &and &not VTLNi) &and ((DCOng &or DCOmsk) &or DCOdg)) &and &not MKRHPA) &and &not EMPTY);
memory used=3.8MB, alloc=40.3MB, time=0.23
memory used=39.0MB, alloc=78.8MB, time=0.89
memory used=96.1MB, alloc=123.9MB, time=2.22
memory used=127.6MB, alloc=411.9MB, time=3.51
memory used=130.5MB, alloc=443.9MB, time=5.71
memory used=136.2MB, alloc=443.9MB, time=7.11
memory used=203.0MB, alloc=475.9MB, time=10.22
memory used=205.5MB, alloc=475.9MB, time=11.71
memory used=326.1MB, alloc=507.9MB, time=14.84

When i delete all the parentheses, everythink work perfectly.

So i assume that when there is too much parentheses dependence maple work not correctly.

Do you have any idea if i'm wrong or not ? Maybe i'm not using the functions correctly ?

Do you have any suggestion on how i should proceed to simplify this equation ?

Thank you for your help.

Dear all,

I get the error "" if I try to plot this:

plot(minimize((s*t)^((s*t)^(s*t))/t^(t^t), t > 0), s = 1 .. 5)

Does anybody know how to get rid of this error? Is it possible/wise to increase the levels of recursion?

Thank you!

This doesn't work directly:

is(RootOf(_Z^3-_Z-1, index = 1)+RootOf(_Z^3-_Z-1, index = 2) = 0);
                                      FAIL

But Maple can compute the bounding interval for a polynomial RootOf (convert(..., RootOf, form=interval)), and evalrC can perform operations on complex intervals:

evalrC(RootOf(_Z^3-_Z-1, index = 1)+RootOf(_Z^3-_Z-1, index = 2));
       INTERVAL(0.6623589782, 0.5622795119, 0.6623589795, 0.5622795122)

evalrC(Re(%));
Error, (in evalrC/INTERVAL) not implemented yet: 4

Re and Im are obviously positive though. Why doesn't Maple try to do that automatically, and also, how do I check if the point is inside the interval? (Without writing my own function to handle real intervals, unions of real intervals, and complex intervals.)

With Typesetting level: Extended, INTERVAL displays only the first argument. So evalr(1/INTERVAL(-1 .. 1)) is displayed as INTERVAL(-infinity .. -1), and INTERVAL(-1,-1,1,1) is displayed as INTERVAL(-1).

I attach a file in which i get an error though it performs.

I made a for do statement which performs perfectly for one loop, but gives an error "unexpected ',' , though performs (i cld not find the errors!).
What does this error state then? How do i remove when I use semicolon to end statement? Can any one help me. Thanks.
 

Download Doubt_A_ReactantValues.mw

Doubt_A_ReactantValues.mw

How does one delete an empty cell. I can't see to do that easily, please see the attached for what I am trying to explain.

Download 2.mw

How do you indent your code neatly ? There should be a feature for automatic indentation, the code structure closesly follows python coding style and having it organized would be very helpful.

Any advise is appreciated.