# Items tagged with mathmath Tagged Items Feed

### Integral and Approximation...

17 hours ago
0 0

Hi all.

Assume that we have partitioned [0,a], into N equidistant subintervals and in each subinterval we have M sets of poly nomials of the following form:

where Tm(t)=tm( namely Taylor Series) and tf is a(final point)
for Example with N=4, M=3 we have:

now we want to approximate a function, asy f(t), in this interval with following form:

If we have:

(Tau is a constant number)
then: can we find L and Z matrices using maple? I have found it manualy but for large M and N this procedure is longsome.

I used Inverse command in maple but the vector's inverse is wrong(operation not defined for Vectors)

Best Wishes

Ph.D Candidate

Applied Mathematics Department

### Approximation with maple...

Yesterday at 6:09 AM
1 4

Hi all.

Assume that we have partitioned [0,a], into N equidistant subintervals and in each subinterval we have M sets of poly nomials of the following form:

where Tm(t)=tm( namely Taylor Series) and tf is a(final point)
for Example with N=4, M=3 we have:

now we want to approximate a function, asy f(t), in this interval with following form:

How can we do this with maple????

how can we find the ci's?????

Thanks a lot

Ph.D Candidate

Applied Mathematics Department

### Advice sought on making input to a 3-d printer usi...

April 22 2014
0 2

I have just begun thinking of trying to make some mathematically defined objects using a 3d printer. I would be happy to hear from anyone who has done this using Maple to prepare input. Pointers for a novice in 3d printing would be appreciated.  I have access to a MakerBot Replicator 2. But the people who have it have only used it to scan objects and make 3d copies of them.

---Edwin

### constructing a special function...

April 17 2014
1 5

Hi all;

Hope all of you  be in good health

I want to construct a special function b_{nm}(t) like:

with piecewise command i did it but the result is incorrect.

any one can help me to do it?

Best wishes

Ph.D Candidate

Applied Mathematics Department

### Minimization Process...

April 04 2014
1 12

Hi all

I have the following segment of maple program which belongs to time delay systems dynamic. here C=X-X0-G.Z-X.Dtau.P+X.Dtau.Z-U.P, is a matrix(vector) which comes from reordering the system terms and my goal is to minimizing J:=X.E.Transpose(X)+U.E.Transpose(U), subject to constraint C=0, but i don't know how to do so.

I will be so grateful if anyone can guide me

best wishes

Ph.D Candidate

Applied Mathematics Department

 > restart: with(Optimization): with(LinearAlgebra): macro(LA= LinearAlgebra): L:=1:  r:=2:  tau:= 1: interface(rtablesize= 2*r+1): Z:= Matrix(      2*r+1, 2*r+1,      [tau,       seq(evalf((L/(2*(iz-1)*Pi))*sin(2*(iz-1)*Pi*tau/L)), iz= 2..r+1),       seq(evalf((L/(2*(iz-1-r)*Pi))*(1-cos(2*(iz-1-r)*Pi*tau/L))), iz= r+2..2*r+1)       ],      scan= columns,      datatype= float[8] );                          Dtau00:= < 1 >: Dtau01:= Vector[row](r): Dtau02:= Vector[row](r): Dtau10:= Vector(r): Dtau20:= Vector(r): Dtau1:= LA:-DiagonalMatrix([seq(evalf(cos(2*i*Pi*tau/L)), i= 1..r)]): Dtau2:= LA:-DiagonalMatrix([seq(evalf(sin(2*i*Pi*tau/L)), i= 1..r)]): Dtau3:= -Dtau2: Dtau4:= copy(Dtau1): Dtau:= < < Dtau00 | Dtau01 | Dtau02 >,          < Dtau10 | Dtau1  | Dtau2  >,          < Dtau20 | Dtau3  | Dtau4  > >;   P00:= < L/2 >: P01:= Vector[row](r): P02:= Vector[row](r, j-> evalf(-L/j/Pi), datatype= float[8]): P10:= Vector(r): P20:= Vector(r, i-> evalf(L/2/i/Pi)): P1:= Matrix(r,r): P2:= LA:-DiagonalMatrix(P20): P3:= LA:-DiagonalMatrix(-P20): P4:= Matrix(r,r): P:= < < P00 | P01 | P02 >,       < P10 | P1  | P2  >,       < P20 | P3  | P4  > >; interface(rtablesize=2*r+1):    # optionally J:=Vector([L, L/2 \$ 2*r]):      # Matrix([[...]]) would also work here E:=DiagonalMatrix(J); X:=  Vector[row](2*r+1,symbol=a); U:=Vector[row](2*r+1,symbol=b); X0:= Vector[row](2*r+1,[1]); G:=Vector[row](2*r+1,[1]); C:=simplify(X-X0-G.Z-X.Dtau.P+X.Dtau.Z-U.P);
 (1)
 > J:=X.E.Transpose(X)+U.E.Transpose(U);
 (2)
 > Minimize(J,{C=0});
 Error, (in Optimization:-NLPSolve) invalid arguments
 > #XP:=-.015+X[1]+add(X[l+1]*f1(l)+X[r+l+1]*f2(l), l= 1..r): #plot([XP,T1], t= 0..1);#,legend= "Solution Of x(t) with r=50"):
 >
 >
 >
 >

### How do I express a function as a variable in Maple...

March 31 2014
3 4

I am new user of Maple. I have an expression like f(x,y)/g(x,y) and I want to have Maple name f(x,y) as something simple like "h" so that later equations write h/g(x,y) instead of the complete f(x,y)/g(x,y), and also to be able to simplify other equations in terms of h.

For example, a=(x+1)(y-5)^2/(x+y-3). Can I get Maple to let h=(x+1)(y-5)^2, so that I get h/(x+y-3) when I ask for a?

Sorry if this question is basic (and my math terminology incorrect), but I have been trying for a while.

### A command like fmincon command(matlab) in maple...

March 30 2014
0 2

Hi all

In matlab software we have a command namely fmincon which minimizes any linear/nonlinear algebric equations subject to linear/nonlinear constraints.

Now my question is that: what is the same command in maple?or how can we minimize linear/nonlinear function subject to linear/nonlinear constraints in maple?

thanks a lot

Ph.D Candidate

Applied Mathematics Department

### Generate Surface using PDE Method...

March 29 2014
0 0

Does anyone has any maple worksheet that generate surface using the PDE method described in this article?  I am trying to learn this method but I am not familiar with the mathematics to do it although the paper gives some description of it.  I hope someone can demonstrate the procedure in Maple.  Thanks

http://www.researchgate.net/publication/259095177_Automatic_shape_optimisation_of_pharmaceutical_tablets_using_Partial_Differential_Equations/file/72e7e52a87ed129d4a.pdf

### How do I prettyprint a summation with conditions?...

March 19 2014
0 5

Is there any simple way to print the sum of a series with exceptions?

For example, the following works (sort of), but its not consistent with mathematical notation, where one would expect to see something like a Sigma^' printed out, and the condition, alongw ith ther limits appear under the Sigma sign:

[Sum(1/(k^2-p),k=0..infinity),And(k<>p)]

### problem with system of ode's or maple ?...

March 19 2014
0 2

hi all.
i have a system of ODE's including 9 set of coupled OED's .

i have  converted second deravaties to dd2 , in other words : diff(a[i](t),t,t)=dd2[i](t) . i =1..9 :

and i have set these 9 equations in form of vibrational equations such :  (M.V22)[i]+(K(t).V(t))[i]+P(t)[i] = eq[i] , where M is coefficient Matrix of second  derivatives , V22 is Vector of second derivaties , for example V22[1] = diff(a[1](t),t,t) , and  P(t) is the numeric part of equations ( they are pure number and do not contain any symbolic function ) and K(t).V(t) is the remaining part of equations such that : (K(t).V(t))[i] = eq[i] - (M.V22)[i] - P(t)[i]  , and V(t) are vector of a[i](t)'s which V(t)[1] = a[1](t) ,

i have used step by step time integration method (of an ebook which i have attachted that part of ebook here), when i set time step of solving process to h=0.01 , i can solve this system up to time one second or more, but when i choose h=0.001 or smaller, the answer diverges after 350 steps . i do not know whether the problem is in my ODS system, or maple can not handle this ?the answer about the time t=0.3 are the same in both steps, but after that, the one with stpe time h=0.001 diverges. my friend has solved this in mathematica without any problem, could any body help me ?! it is urgent for me to solve this problem,thnx everybody.

ebook.pdf  step_=_0.001.mw  step_=_0.01.mw

### how to get 2 solutions from Maple equation which c...

March 17 2014
1 4

restart;
g:=0.88641:
e:=2.53128:
eq:=tan(g)= e*sin(f)/(1+e*cos(f)):
fsolve(eq,f);

gives  1.19749

What command/option do I need to get both solutions like with Mathematica:

g = 0.886461;
e = 2.53128;
eq = Tan[g] == (e Sin[f])/(1 + e Cos[f]);
NSolve[eq, f]

(*   {{f -> -2.56623}, {f -> 1.19756}} *)

thanks

### How do I best treat "delta" in Maple?...

February 09 2014
0 14

In physics as in math, we often use delta to indicate a (small but finite) variation in a parameter (e.g. delta x). Sometimes Delta (capital delta) is used for a larger variation, and there are even constructs like delta Delta x (a small variation of a larger variation in x). (Don't laugh or frown, this is being done & makes sense in certain situations.)

How do I write this best in Maple, esp. when I use 2-d math and am working on a (live-) script that may be handed out to others incl. students,? I.e. the appearance matters. Just writing delta x is interpreted (in 2-d input) as delta*x which is not what is meant (and leads to funny effects after the first simplify). If I write deltax (one word) then delta does not typeset in its proper greek form, which becomes an issue if you have many of these. I can write delta(x) and that often works (as long as you don't try to differentiate by x), but the typeset equation does not look right either (delta is not a function of x).

Is there a god way of doing this, or am I hitting a wall here?

TIA,

Mac Dude

### How to replace D-notation with standard partial de...

February 02 2014
1 12

I am trying to illustrate the chain rule for multivariet functions

diff(f(u(x,y),v(x,y),x)

The Maple responce is D1(f)(u(x,y),v(x,y)*(partial of u(x,y) wrt x) +..etc

I would like to replace the D- notation with the standard notation for the "partial of f wrt u" for obvious reasons - this is what students are familar with. The convert cmnd Doe Not Work in this case.

Similarly the cmnd diff(u(x,y),v(x,y),x,x) gives rise to D1,D11, D12 symbols which I would likee to convert to standard partial notation.

All this is a BIG DEAL when trying to illstrate the chain rule in Cal III.

Joe Salacuse

Mathematics

Kettering University

### Slides of VII Workshop 2014...

January 08 2014 Maple 17
4 1

Slides of the presentation at the VII Workshop Fast Computational and Applied Mathematics developed in graduate school at the National University of Trujillo. January 8, 2014.

Visualización_Geomét.pdf

L. Araujo C.

### Quick question about the solve function...

December 19 2013
1 5

EDIT:EDIT: I found what I was looking for. Thanks!

eq:=(V^(1-r/(r-s))*V*k/(r-2*s)+_C1)*V^(r/(r-s))=0;

$\left&space;(&space;\frac{V^{1-\left&space;(&space;\frac{r}{r-s}&space;\right&space;)}*V*k}{r-2*s}+C1&space;\right&space;)&space;*V^{\frac{r}{r-s}}=0$

solve(eq,C1);

Can anyone tell me why nothing happens when I solve the above equation for C1.

I've been coming across this problem a few times lately, but sometimes when the equations are less complicated it does work from time to time.

Any help would be greatly appreciated.

EDIT:  Thanks Markiyan Hirnyk

But I'm still having some trouble.

f:=t->(-r*t+s*t+V)^(r/(r-s));

eq2:=diff(C*f(t),t)+C*f(t)*r/(V+s*t-r*t)=s*k*t;

solve(eq2,C);

When I try solving eq2 nothing happens.

This time C is just a variable I used and not one Maple generated.

So why doesn't it work with this particular equation?

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