When trying to contract the Christoffel with some vector

with(DifferentialGeometry):
with(Tensor):
DGsetup([r, phi], M);
g := evalDG(dr &t dr + r^2 * dphi &t dphi);
ContractIndices(Christoffel(g), D_phi, [[2, 1]]);

I get the following error:

Error, (in DifferentialGeometry:-Tensor:-ContractIndices) expected 1st argument to be a tensor. Received: _DG([["connection", M, [["con_bas", "cov_bas", "cov_bas"], []]], [`...`]])

What can I do about that?

I am trying to find the pdf of the inverse of a random variable X, that represents a distribution I defined. I currently have : 

with(Statistics):
T:=Distribution(PDF=(x->piecewise(0<x and x<1,1/4,3<x and x<5,3/8,0)));
X:=RandomVariable(T);
PDF(X,u);
CDF(X,u);
Y:=1/X;
T1:=RandomVariable(Y);

but this seems to be incorrect as I get a message saying T1:=RandomVariable(Y) is being passed a wrong argument. 

What is the right way to obtain the pdf of 1/X?

why the the software can't solve the integral like ∫xdlnx？

Thanks in advance for your help.

Hello, 

      I am a student doing some self study over the summer trying to work through some of the John Taylor computer problems from his classcial mechanics book. Currently I hit a snag that most likely comes from the fact I am not well acquinted with Maple for solving IVP and DE's (we used Matlab in my DE class). I just need to know how I remove the following error:

Error, (in dsolve/numeric/SC/IVPsetup) initial conditions must be numeric

Here is a copy of my code:

R := 5;
5
g := 9.8;
9.8
deq1 := {diff(x(t), [`$`(t, 2)]) = -g*sin(x(t))/R, x(0) = 20};
/ d / d \ \
{ --- |--- x(t)| = -1.960000000 sin(x(t)), x(0) = 20 }
\ dt \ dt / /
dsol1 := dsolve(deq1, numeric);
Error, (in dsolve/numeric/SC/IVPsetup) initial conditions must be numeric

My hunch is that I need to set x'(0)=0 or something like I do not have enough intial values to solve the problem, but I could be wrong. Anyway anyone who can point out my mistake feel free to do so! Thank you!

hi.please help me for solve this integral

thanks aloterror.mw

(Phi)(x,theta,z,t):=-Phi[0].sin((m*Pi*(x-x[0]))/(L)).cos(n*theta)*cos((Pi.z)/(h)).sin(omega*t):n:=1:L:=2:m:=3:x[0]:=6:h:=1/(2);
print(`output redirected...`); # input placeholder
1
-
2
evalf(Int(diff(Phi(x, theta, z, t), theta, theta), z = -(1/2)*h .. (1/2)*h));
print(`output redirected...`); # input placeholder
/0.2500000000
| / / /3 \\
| |(Phi[0]) . |sin|- Pi (x - 6)|| . (cos(theta))
| \ \ \2 //
/-0.2500000000

\
cos(2 Pi z)| . (sin(omega t)) dz
/

DEtools[DEplot](diff(x(t),t)=-abs(x(t)),x(t),t=0..40,[x(0)=1],numpoints=1000,dirgrid=[30,30],linecolor=blue)

i just need 1 at a11 position of a square matrix. do not need zeros like in complete pivoting. plz help

I want to plot curves with Japanese title and labels. I want to plot through an external java program. Is it possible?

When I tried, I am getting control character unexpected error.

Hi, Everyone.

I'm trying to figure out how to make a graph (actually a "line") change color based on certain criteria so I can create a Maple Application.

I've figured out the following, which indicates the sign of the graph by the color, but it's way more complicated than it ought to be.

It's also not robust as I need it to be, this happens to depend on the zeros occuring at integer values.  I could deal with that on a case by case basis, but not for something automatically.

I'm at a loss; maybe I'm not Googling the right things... maybe Maple can't do this (although I'd heard color tools were being added in Maple 16).

Does anyone have any suggestions?

Thanks In Advance!

Joseph

Am I right that using methods of the 1-forms (that implemented in liesymm or DESOLV), we can always generate determining equations for ODE, that solved for highest derrivative?

Hi, I am learning GR and new to maple. I played with maple's DifferentialGeometry package.

While duplicated the maple GR example, in DGsetup([t, r, theta, phi], M1, verbose),

I got the error,

DGsetup([t, r, theta, phi], M1, verbose)

The following coordinates have been protected:
[t, r, theta, phi]

The following vector fields have been defined and protected:

Error, (in Typeset:-Tdisplay[true]) `alias` does not evaluate to a module

 I don't know how to fix it. Can anyone kindly help?

Thanks

I'm trying to build a Maple procedure that will generate vector fields on a metric with certain properties. Working with metric g over the coordinates {u,v,w}, call the field X = (a(u,v,w), b(u,v,w), c(u,v,w)). The field should satisfy <X, X> = 0 and have the directional covariant derivative of X in the direction of each coordinate vector field = 0 (with resepct to the Levi-Civita conenction).

Basically, these conditions yield a system of 3 PDEs and an algebraic expressionin terms of a,b,c. I've been trying to solve them using pdsolve, but I'm getting the error message:

>Error, (in pdsolve/sys) the input system cannot contain equations in the arbitrary parameters alone; found equation depending only on _F1(u,v,w): _F1(u,v,w)

I've attached my worksheet. Can anyone help me out?

Thanks! ppwaves.mw

Here we develop the factoring in common factor, simple and complete square blade, plus simple equation systems with graphic and design, and graphic solution of the quadratic equation using components in maple 2015.

Factorizacion.mw

(in spanish)

L.AraujoC.

Hello,

i am trying to get a latex output which equals the displayed maple equations, where i am using alias/surpress or declare to shorten the dependencies of my derivatives. Whereas in Maple this looks how i want it to look like, i can not get the latex() command to apply the aliases. Instead it replaces the short forms with the long terms before creating the latex code. Is there anyway to get a latex output directly from the displayed math WITH alias?

2 small examples:

Both yield  $ X \left( a,b,c \right)$ whereas i would like to get X. Simply substituing changes the partial differential symbol to "d" in the latex output and makes the equations unuseable, so this is no option i guess..

Thanks a lot for any suggestions!