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hello

took this problem from a uk tv program.

4 dancers are initially at the 4 corners of a square, edge length 4 meters. every dancer moves towards the person on their left.

i want to know the equations of the spiral. the arc length of each path should be 4m.  also an animation of the 4 spirals would be great. 

dance.mw

under the heading "more spirals" the closest one is r(t)=1/t (decreasing modulus)

http://mathematische-basteleien.de/spiral.htm

 

Hello,

Anyone here know how to use the read command. I tried to use it to call and run the particular code but it didnt work. It produce this such error 

> read "02ExactSoln.m";
Error, could not open `02ExactSoln.m` for reading

I have no idea how to fix it. Or do I need to locate the code in any specific folder. 

Thanks

 

 

Here is the function I want to find the inverse of 

 U(x):=-(s^2/(s^2+1)+1/(s^2+1)-1)*exp(sqrt(s)*x/sqrt(phi))/(s^2+1)+exp(-sqrt(s)*x/sqrt(phi))/(s^2+1);

where phi>0

Now taking the inverselaplace of U(x)

 u:=invlaplace(U(x),s,t);

which give me an unevaluated integral.

Any idea, how to get the complete inverse, maybe interms of erf?

Hi,

  I have the following input

f:=x^2*exp(-1.2*x);
maximize(f, x=0..100,location);

 Maple gives me the location is x=1.25. However, how should I do to obtain this position?  If I write

 

a:=maximize(f, x=0..100,location);

 

  Seems it do not work :(

 

  I may try fsolve at the maximum value, but it seems to be awkward..

 

Thank you very much!

  

Is it possible to have an input box, where the student can give an input (integer) and this is then used in the following questions in an assignment?

e.g. in the first question the student is asked to give his student number, in the second question this number is used to create random parameters.

Hi guys.

I want to know how can I make the maple to give final response of a simple trigonometric function, e.g sin(pi/6). When I type sin(pi/6) in the command line and then press enter, maple give the same, I mean sin(pi/6) at the next line. I want 0.5 as the final response not sin(pi/6) again. Simplify command does not work for me in this case.

Thanks in advance.

When solving a simple assignment problem in Maple 2015.1 the bug occurs:

 

In Maple 2012 there are no problems:

A := Matrix([[1, 7, 1, 3], [1, 6, 4, 6], [17, 1, 5, 1], [1, 6, 10, 4]]):

n:=4:

z:=add(add(A[i,j]*x[i,j], j=1..n), i=1..n):

restr:={seq(add(x[i,j], i=1..n)=1, j=1..n),seq(add(x[i,j], j=1..n)=1, i=1..n)};

sol:=Optimization[LPSolve](z, restr, assume=binary); 

 

 

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!

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