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Hello

I am working on a project where I need to find the parameters of the formula:

1/2*a*erfc(1/2*2^(1/2)*(-x+m1)/s1)+(1/2-1/2*a)*erfc(1/2*2^(1/2)*(-x+m2)/s2)

which is the formula for the cumulative distribution for two gaussian peaks, one with average m1 and standard deviation s1, the other m2 and s2, with weights a and (1-a). I have data in excel that form the gaussian distribution but now I need to find the parameters of the formula that fits these data.

Is there a command in maple to find these parameters or how do I start? And do I need to upload the data from excel to maple or do I need to insert only some values?

Some one who could help me, because it is really hard and I find no information for this.

Hasselhof

Hi !

I wish to solve a differential equation with an initial condition of the type D(f)(a)=b, where 'a' and 'b' are arbitrary real constants and are entered this way symbolically. Maple interprets D(f)(a) as a function which depends on a new variable 'a' and gives the error:

 

Error, (in dsolve) found differentiated functions with same name but depending on different arguments in the given DE system: {f(a), f(psi)}

(the differential equation is for a function f(psi) which was defined previously)

 

How can I pass this initial condition f'(a)=b (a,b being constants, but arbitrary) to the Maple dsolve command?

I have been browsing the web and looking at manuals, but always find D(f)(0)=3 or any other combination with numbers only.

Thank you in advance.

Regards,

              Michael

 

 

I have the following transition rate matrix. Upto m the matrix follows a patern and after that the patern changes but repetative structure is there upto n. In this problem m=4, n=9. How to write these entries using for loop in maple?

Matrix.pdf

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.

These both work the same way

s1:=StringTools:-Join(["this is a ","test"]);
s2:=cat("this is a ","test");

When should one not use cat() command? It seems much simpler than Join. Are there cases where cat() will not work and Join will work?

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
/

 

In Maple TA in blackboard I am creating an assignment. Each week a part of the assignment will be posted. I was wondering if it is possible to have the same random variables in differnet assignmemts. That way the students can use their prior work. 

So in week one the students will get a set of random variables. But in week two a new assignment is posted were I want the same variables to come up for each student. Is this possible? (all students will have their own unique set of variables)

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

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