Hello,

I would like to solve the differential equation in the following link:

http://www.utdallas.edu/~frensley/technical/nanomes91/node2.html

Without using any explicit discretization. Is it possible to solve this equation with a Maple dsolve comand and some boundary condition option?

I am continuing work with buttons and I wanted to be able to clear graphs with a button.  I understand how to communicate with the button because of other posts by members that have been very helpful.    I want the button to be able to delete the graphs that I have drawn in Plot0.

Is there a way this can happen? Or do my students just need to type a new equation in to the mathematical expression box to plot new functions?

Any help is appeciated. I could not find anything online that I could get to work. I have included the document

Nick

I'm trying to create and populate the Array `A` with a sequence of lower triangular matrices based on the following relation:

A[k+1][i,j] = a (1+k) A[k][i,j] + b ((1+j) A[k][i-1,j] - j A[k][i-1,j-1])

The rows and columns of each matrix are given by i and j; a and b are scalars. The structure of A is not important provided a matrix can be accessed for a given k. The highest k value will not be more than about 100.

The starting matrix for k=1 is

[-1  0]
[ 1 -1]

Any guidance on where to start with setting up the appropriate procedure would be greatly appreciated.

Thanks.

I have a procedure that takes an object, i.e. a module, as an argument. On grounds of the properties of that object, the procedure should return a certain map. But I hit a snag, the gist of which is along the following lines (just an example):

M := module()
   export dim;
   dim := 2;
end module:

F := proc(m::`module`)
   (x::Vector(m:-dim)) -> something
end proc:

My problem is that F(M) produces

rather than

How can I force m:-dim within F to be evaluated?

i want to solve this pde,but i do know how to write my boundary or initial conditons,actually my dependent variables were x and y, i changed x to t,since i faced an error that pde solver needs time=varname , but i could not solve my problem,do anyone know how to insert my boundary conditions ?! please help,thnx
maple.mw

I need a procedure to simplify rational functions r(x,y) = p(x,y)/q(x,y)  where p(x,y) and q(x,y) are polynomials in Z/(2)[x,y].

For example suppose r(x,y) = (1+x+y)/(x^2+x*y+y+1) then mod 2 this reduces to 1/(1+x) since 

            Factor(x^2+x*y+y+1) mod 2 = (1 + x + y) (1 + x)

I wrote a procedure to do this using Factors mod 2, but I wonder if there is a builtin procedure to make such simplifications that might be more efficient.  For now 2 variable is fine, but later I may want more than 2 variables.

Edwin

How can I create a new object from a stanrd, defined in a given metric? For example I want to define an object by convolution of two indices of the Christoffel symbols? I cannot even to see components of such object.

Many thans for an explanation

Leonid

Hi, there i want to basically plot the graph attached. It is basically the graph y= 2x^2 transformed to y = x^2. I can plot them, but how do they get the arrows showing the transformation and the arrows on the axis. Any help would be appreciated.

Thanks

okay so im quite confused, im trying to write a procedure that prints the orbit of a 2x2 matrix through a given list of points.  our arguments should be a a (2x2) matrix, a list L of points represented by 2 vectors, ie (2x1) matrices and a natural number N. Returnvalue : NULL

a side effect should be to 

A^i.L[j] for i = 0 ... N and j = 1 ... nops(L)

thus, an example, if the proc is called P, then 

P(Matrix([[0,-1],[1,0]]),[Matrix([[1],[1]]),Matrix([[1],[0]])],2) 

should plot the points  

(1,1) ,(-1,1) , (-1,-1)  for the 1st point  and 

(1,0)  ,(0,1) , (-1,0) for the second

thanks for any help in advance

Hi, how would you add arrowheads to the x and y-axis to show that they continue.

Thanks 

Composite1:=proc(g,f)
Flist := indets(f): Glist := indets(g): gof:=g:
Subslist1 := [seq( Flist[i]=q, i=1.. nops(Flist))]:
return subs(q=f,subs(Subslist1, gof)): # g(f)
end proc:
#F(g o f) = F(g) o F(f) = F o g o f = (F o g) o (F o f)
Functor := (1/2)*(-y*t2-x*t1-y*t3+sqrt(y^2*t2^2+2*y*t2*x*t1+2*y^2*t2*t3+x^2*t1^2+2*x*t1*y*t3+y^2*t3^2-4*x*t4*y*t9-4*x*t4*y*t8-4*x^2*t4*t7-4*y^2*t5*t9-4*y^2*t5*t8-4*y*t5*x*t7-4*y^2*t6*t9-4*y^2*t6*t8-4*y*t6*x*t7))/(x*t4+y*t5+y*t6);
F1:=x+2;
G1:=3*x+5;
gof:=subs(x=F1, G1);
osys := Composite1(gof, Functor) = Composite1(Composite1(G1, Functor),Composite1(F1, Functor));
sys1 := subs(x=3,subs(y=2, osys));sys2 := subs(x=5,subs(y=1, osys));
sys3 := subs(x=1,subs(y=5, osys));sys4 := subs(x=1,subs(y=2, osys));
sys5 := subs(x=2,subs(y=5, osys));sys6 := subs(x=5,subs(y=2, osys));
sys7 := subs(x=2,subs(y=1, osys));sys8 := subs(x=3,subs(y=5, osys));
sys9 := subs(x=5,subs(y=3, osys));
res:=solve([sys1, sys2, sys3, sys4, sys5, sys6, sys7, sys8, sys9], {t1,t2,t3,t4,t5,t6,t7,t8,t9});
simplify(%);
`~`[lhs](select(evalb, res));

alpha:= (1/2)*(-y*t2-x*t1-y*t3+sqrt(y^2*t2^2+2*y*t2*x*t1+2*y^2*t2*t3+x^2*t1^2+2*x*t1*y*t3+y^2*t3^2-4*x*t4*y*t9-4*x*t4*y*t8-4*x^2*t4*t7-4*y^2*t5*t9-4*y^2*t5*t8-4*y*t5*x*t7-4*y^2*t6*t9-4*y^2*t6*t8-4*y*t6*x*t7))/(x*t4+y*t5+y*t6);
g := -y/x;
f := (-x+sqrt(x^2-x*y-2*y^2))/(2*y+x);
subs(p=f,subs(q=f,subs(x=p,subs(y=q,g))));
g := (1/2)*(-x+sqrt(x^2-4*y*x-4*y^2))/(x+y);
f := x*y;
gof := subs(p=f,subs(q=f,subs(x=p,subs(y=q,g))));
lhsgofoalpha := subs(q= alpha,subs(p=alpha, subs(x=p,subs(y=q,gof))));
foalpha := subs(p= alpha,subs(q=alpha,subs(x=p,subs(y=q,f))));
rhsgofoalpha := subs(x= foalpha,subs(y= foalpha, g));
osys := lhsgofoalpha = rhsgofoalpha;
sys1 := subs(x=3,subs(y=2, osys));
sys2 := subs(x=5,subs(y=1, osys));
sys3 := subs(x=1,subs(y=5, osys));
sys4 := subs(x=1,subs(y=2, osys));
sys5 := subs(x=2,subs(y=5, osys));
sys6 := subs(x=5,subs(y=2, osys));
sys7 := subs(x=2,subs(y=1, osys));
sys8 := subs(x=3,subs(y=5, osys));
sys9 := subs(x=5,subs(y=3, osys));
res:=solve([Re(sys1)=0, Re(sys2) =0, Re(sys3) =0, Re(sys4) =0, Re(sys5) =0, Re(sys6) =0, Re(sys7) =0, Re(sys8) =0, Re(sys9) =0], {t1,t2,t3,t4,t5,t6,t7,t8,t9});

I want to taylor-expand cos(x) to the powers of two, four, and six, then to make equations which does not contain O(x^2) etc. and to obtain its value at x=0.1.

For that, I wrote as the following.
(1):
a:=seq(taylor(cos(x),x=0,i),i=[2,4,6]);
convert(a),polynom);

(2):
a:=seq(taylor(cos(x),x=0,i),i=[2,4,6]);
seq(convert(op(i,a),polynom),i=[2,4,6]);

(3):
a:=seq(taylor(cos(x),x=0,i),i=[2,4,6]):
convert(a,polynom);

All of the above were not good.

On earth, I couldn't pick up each of the result of
a:=seq(taylor(cos(x),x=0,i),i=[2,4,6])
with op(1,a).

How can I solve this problem?

I have created a diagram with "plots" and "plottools" that involves the line command creating a line in 3-space.  It works just fine on all of my machines and versions of Maple but it fails on Maple 17 in the Windows 8 environment.   By "fai;s" I mean that it does not draw the line; it does not generate an error message.   Any idea what's happening? 

I wrote the following code inside a code region in order to implement a scalar product for lists:

m:= module() option package; export `*`;
    `*`:= proc( a::list, b::list) option overload;
        return add(i, i  in zip((x, y)-> x*y, a, b));
    end proc;    
end module;
l1:=[1,2,3,4];
l2:=[4,1,0,5];
with(m);
l1*l2;

when i run the code I sometimes get the desired result ->26

but sometimes I get

I don't have any clue, where this weird behaviour comes from.

Any help would be greatly appreciated.