MaplePrimes Questions

F(n,n+1),2) = F(Product(x, k=1..n), 2)

how to solve function F?

Update
 

Above equation is wrong, below is newly updated 

Expect F is product operator

F(2,3) + 2 = F(2,4)

F(3,4) + 3 = F(3,5)

solve([ F(1,2)+1=F(1,3), F(n,n+1) + n = F(n,n+2), F(n,n+1)= F(summation(k,k=1..n),2)],F) assuming n > 0

Expect F is new operator
solve([ F(1,2)*1=F(1,3), n*F(n,n+1) = F(n,n+2), F(n,n+1)= F(product(k,k=1..n),2)],F) assuming n > 0

Let A be the set of the first 1000 odd natural numbers. Use Maple’s commands for set operations to determine how many elements in A are also triangular numbers or prime numbers.

Use Maple to find all quintic polynomials f(x) such that f(1) = 2, f(2) = 3, f(3) = 4, f(4) = 6, f(5) = 10. Is there a cubic polynomial satisfying the conditions? If so, give this polynomial.

Use the bisection method in a while loop to estimate the root of f = (x − 1/9)(x − 2)(x − 3) which lies between 0 and 1 to an accuracy of 10^−4 .  

Good afternoon! I can not give such terms in the procedure, simplify and evalf do not help. Why does it write three lambdas instead of a lambda in a cube?
What can I do about it?


help.mw
 

 

I want to simulate the behaviour of a mass-spring system under an oscillating acceleration, but I also want that the mass remains between two rigid walls (no bouncing has to be considered).
Here is the notional example I use in the attached file (here x(t) will have to verify x(t) >= 0 and x(t) < 2).

s := t -> 10*cos(t)-x(t):

sys := { 
  diff(v(t), t)=s(t), 
  diff(x(t), t)=v(t), 
  v(0)=0, 
  x(0)=0
}:

When the mass reaches one wall it gets stucked at it until the acceleration allows it to take off from this wall. It can then move to the opposite wall and possibly get stucked at it waiting for appropriate conditions to fly again.
Here are two images to help you understand what happens:

  1. the first one represents the "unbounded" solution of the system above
  2. the second is the "bounded" solution
     

To obtain the right picture I construct the solution piecewise (the method, based on events and the use of discrete variables, is described in the attached file).
For some reasons I would like to build the global solution "in one shot" and no longer have to assemble it from elementary pieces (the blue, red and gray chunks on the right figure).
I've tried to do this through events but  I have failed so far (an ettempt is presented in the attached file).

From_wall_to_wall.mw

Could you show me how to use "events" to handle this problem?

Thanks in advance

Hi there.

It looks strange but simplify/symbolic cannot handle expression in file:

example.mw

Only after expanding numerator and denominator by hand.

I think simplify/symbolic should be smarter.

The following example (from help, direct call, without with) does not work.

restart;
(Q[`0`],Q[`1`],Q[`+`],Q[`-`],Q[`*`],Q[`/`],Q[`=`]) := (0,1,`+`,`-`,`*`,`/`,`=`):
A := Matrix([[2,1,4,6],[3,2,1,7],[0,0,5,1],[0,0,3,8]]):
LinearAlgebra:-Generic:-Determinant[Q](A, ':-method' = ':-BerkowitzAlgorithm');

==> error, (in hasoption)

We must use:

LinearAlgebra:-Generic:-Determinant[Q](A, method=LinearAlgebra:-Generic:-BerkowitzAlgorithm); # 37

which I suppose is not intended!
That's because the keyword name in the code appears as 'BerkowitzAlgorithm' instead of ':-BerkowitzAlgorithm'
(The problem occurs because there is an export LinearAlgebra:-Generic:-BerkowitzAlgorithm). 
 

Hi, everyone, here is my maple code

 

restart;
In := 5.75*10^(-12);             
M := 1000;

E := 10^12;

V := 100;

m := 2300;

K := 10^9;

A := E*In;
B := M*V^2;

C := 2*M*V^2;

F := M + m;

G := K;
pde := A*diff(w(x, t), x $ 4) + B*diff(w(x, t), x $ 2) + C*diff(w(x, t), x, t) + F*diff(w(x, t), t $ 2) + G*w(x, t);
tmax := 0.05;
xmin := 0;
L := 1;
bc := w(0, t) = 0, w(L, t) = 0, D[1, 1](w)(0, t) = 0, D[1, 1](w)(L, t) = 0;

ic := w(x, 0) = 0

pdsA := pdsolve(pde, eval({bc, ic}, L = 1), numeric, spacestep = 0.01)

 

 

 

I keep getting error message: Error, (in pdsolve/numeric/par_hyp) Incorrect number of initial conditions, expected 2, got 1

but when i change the pde to:

pde := A*diff(w(x, t), x $ 4) + B*diff(w(x, t), x $ 2) + C*diff(w(x, t), x, t) + F*diff(w(x, t), t) + G*w(x, t);

it works, although that is not what i am aiming for at all.

how may i solve this? my goal is to find w(x,t)

 

Finite Fields package seemed very useless for my purpose.

Is there a way to do some linear algebra computation (finding rank, solving linear systems, finding span of vectors) over a finite field (GF(2), GF(5), GF(3^5) etc) ?

Thank you in advance

Dear all

I have the following proc I, I need a help so that the proc run without error. 

I get Error, invalid =

 

Code_eigenvalues_eigenvectors.mw

 

Thank you for any help 

Determine the sert of point  Z in complex plane isuch that  l2z-il=Im(z+1-i)

Lets say I wanna write a procedure DrawSpaceCurve3d. 

 

DrawSpaceCurve3d:=proc(fnc::algebraic, vars:name,h::integer, xvalue::range=a{integer}...b..{integer})
plots:-spacecurve([vars, h, funk(vars, h)], ':-x' = 'xvalue')
end proc; 

How I try to run this procedure, then I get the following error. 

"Error, (in Plot:-SpaceCurve) parameter range in the form name=range is missing"

So my question is it possible to get Maple to accept that I write DrawSpaceCurve3D(x^2*y, 2, xvalue=[-5..5]) 

I know the y - curve is missing, but I would like to see if I can get Maple to accept this kind of input?
 

I am trying to solve three simultaneous PDE where the first two PDEs are 1D while the third is 2D. When using pdsolve with numeric option I am getting the following error

Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {Tg(t, z, 0.6985e-1)}. Can someone please help me with this.

 

restart;
T_well := 10. + 0.026*z;

PDE_in := -0.493381*diff(Ti(t, z), z) + diff(Ti(t, z), t) = 0.000176303*(-Ti(t, z) + To(t, z));
PDE_out := 0.186546*diff(To(t, z), z) + diff(To(t, z), t) = 0.0397694*(Tg(t, z, 0.06985) - To(t, z)) + 0.0000666597*(Ti(t, z) - To(t, z));
PDE_g := 0.22828*10^7/3.5*diff(Tg(t, z, r), t) = diff(Tg(t, z, r), r)/r + diff(Tg(t, z, r), r, r) + diff(Tg(t, z, r), z, z);
PDE := {PDE_g, PDE_in, PDE_out};
IC := {Tg(0, z, r) = T_well, Ti(0, z) = T_well, To(0, z) = T_well}
BC := {3.5*D[2](Tg)(t, 2000, r) = -3/40, 3.5*D[2](Tg)(t, z, 0.06985) = 0.0397694*(Tg(t, z, 0.06985) - To(t, z)), Tg(t, 0, r) = 10, Tg(t, z, 50) = 10 + 0.026*z, To(t, 0) = 10, To(t, 2000) = Ti(t, 2000)}
pdsolve(PDE, IC, BC, numeric)


 

with(plots);
a := -Pi;
b := Pi;
implicitplot3d(1/2*(sin(2*x)*cos(y)*sin(z) + sin(2*y)*cos(z)*sin(x) + sin(2*z)*cos(x)*sin(y)) - 1/2*(cos(2*x)*cos(2*y) + cos(2*y)*cos(2*z) + cos(2*z)*cos(2*x)) + 0.15 = 0, x = a .. b, y = a .. b, z = 1/2*a .. 3/2*b, grid = [70, 70, 70], style = patchnogrid, shading = xy, lightmodel = light2);
 

 

Hi! Is it possible to get more clear mesh plot when the grid is such large? 

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