Hey all, I am playing around with different numerical ODE solvers in Maple, and with method=dverk78, I get an odd error that maybe someone here can help me interpret: > S2 := dsolve([accx, accy, IC], numeric, method = dverk78); S2:=proc(x_dverk78) ... end; > S2(0.1000000e-14); Error, (in S2) step size

It took me a couple of days just to write the below Maplet code which loads a CSV file (time series organized in

columns where the first column is date/year etc and first row contain the names of the stocks)

and displays the stock names in a dropdownbox. Now I want to plot my selection from my dropdownbox

but now I have a new problem. When I include the "onchange = AC"

command in the drop1 command line in order to update my selection from the dropdownBox

I get an error message :

 

HI all,

 

Thanks in advance for having a look at this topic.

I have problems with finding the inverse function for this equation

(10088-10088*exp(-x))/(72*x+76)/((1-exp(-x))/x+10088/3/(72*x+76)-1)

A solution exists for the range that I am interested in x>0.5  However I can not get an output for the inverse function even when assuming x>1

I am not very experienced in Maple so perhaps I am doing a small thing wrong. Any help on this would be highly appreciated!

 

I want to retrieve data from google finance to do some analysis. Since the amount of data pieces are very huge. To aviod a huge amount of copy and past operations, I need to do it automatically in maple. So my question is how can I reduce the work in Maple as much as possible? I know google offers some APIs for retrieving data. Can I utilize that in Maple?

I want to get the length of a list. Is there any command available for that? For example, I want it return 2 for the list [8374, 32875], since it has two items.

 

I type in:

--------------------------------------------------------------------

RET := λbar*R :

RET[Sigma] := cos(RET)+RET*sin(RET):

C6[Sigma]+(C3[Sigma]*RET[Sigma])^2/(4*De);

--------------------------------------------------------------------

It displays fine on my GUI, but when I copy and paste it into a text editor I get:

RET := λbar*R :

RET[Sigma] := cos(RET)+RET*sin(RET):

C6[Sigma]+(C*3[Sigma]*RE*T[Sigma])^2/(4*De);

--------------------------------------------------------------------

M:=Matrix([[1,2,2],[3,2,0],[4,5,7],[8,3,5]]);

I want to pick the 2nd column (and/or row) from the above matrix and put the values into a vector, how can I do this?

results:

V1=[3,2,0]

V2=[2,2,5,3]

 

I want to build a list or vector out of 2 vectors containing values and 2 lists containing the order in the total list (or vecotr), I was wondering if there is a very simple way to do this instead of using loops?

NbNode:=6;
These are values:
U:=<1,2,2,3>;
UElim:=<0,5>;

And these are orders:
Elim:=[2,4];
ListEqn:=[seq( i, i=1..NbNode )]:
ListEqn:=subsop(seq(i=NULL, i in Elim), ListEqn);

The final result should be:

Utot=[1,0,2,5,2,3]

 

why doesn't "coeff" command work on this equation?

f=zin-z2(z3(z1(zin+I*z1*tan(beta1*d1))+I*z3*(tan(beta3*d3))(z1+I*zin*tan(beta1*d1)))
+I*z2*(tan(beta2*d2))(z3*(z1+I*zin*tan(beta1*d1))+I*z1(zin+I*z1*tan(beta1*d1))*tan(beta3*d3)))/(z2(z3(z1+I*zin*tan(beta1*d1))
+I*z1(zin+I*z1*tan(beta1*d1))*tan(beta3*d3))+I*z3(z1(zin+I*z1*tan(beta1*d1))+I*z3*(tan(beta3*d3))(z1+I*zin*tan(beta1*d1)))*tan(beta2*d2))

a0 := coeff(f, zin, 2);
b0 := coeff(f, zin, 1);
c0 := coeff(f, zin, 0);

Hey all, I want to solve ODEs with Maple but for some reason I am not getting any output. No error, just no output. Can someone tell me where I am going wrong (this DE is just a random example I pulled out of the air): > eqn := diff(y(t), `$`(t, 2))+1/y(t)^2 = sin(t); > dsolve(eqn, y(t));

restart:
A:=Vector(<2*u[1]+u[2],3*u[1]+u[3],5*u[2]-u[3]>);
U:=<1,2,3>;
for i to 3 do
A:=eval(A,u[i]=U[i]);
od;

How can I do this in a simpler and faster way? I will do this procedure for many times with larger vecotors and matrices.

TIA

 

Is there a way to combine Arrays, like 5 Arrays called a,b,c,d,e into a single Array? a,b,c,d and e are all the same size.

Ive been using.

A := Array(...) (whatever size I need)

for k to z do
  A[k] := a[k]
end do:

for k to z do
  A[k+z] := b[k]
end do:

for k to z do
  A[k+(2*z)] := c[k]
end do:

for k to z do
  A[k+(3*z)] := d[k]
end do:

for k to z do
  A[k+(4*z)] := e[k]
end do:
 

Good Afternoon everybody,

Would anybody please see why Maple would not substitute the list  Lx :=[...], and Lz[....] into the equation in the attached procedure called inertia. My goal is to output the mass moment of inertia of the machine foundation.

Regards,

Hey all, I have a system of differential equations that I want to solve using Runge Kutta, but for hte life of me I can't figure out the syntax for the command. Maybe someone here can point out where I am going wrong? > accx := m*(diff(x(t), `$`(t, 2))) = -q*A*sin(w*t)-q^2/(x(t)^2+y(t)^2); > accy := m*(diff(y(t), `$`(t, 2))) = -q^2/(x(t)^2+y(t)^2); > IC := x(0) = -0.1322943021e-8, y(0) = 0.793765813e-10, (D(y))(0) = 0, (D(x))(0) = 3839294.99; > RungeKutta([acc, acc2], IC, 0.1e-14);

We want to add 5 to the list L:

with(ListTools):

L:=[1,3,6,7];

L:=[L,5];

L:=Flatten(L);

 

I think there must be an easier way to do this, I would be thankful if someone let me know.