Hi all. I'm using pdsolve to find linearly independent solutions for two partial differentioal equations. I can solve them seperatly by "pdsolve", but when I try to solve them at the same time to get answers that fit in both of the eauations, I get an error message. I need to be able to solve them as a set of equations, as I have bigger examples. Here are the equations and outputs: 

PDE[1] := diff(f(theta[I], theta[A], theta[B], theta[AB]), theta[AB]);

PDE[2] := -(diff(f(theta[I], theta[A], theta[B], theta[AB]), theta[I]))+diff(f(theta[I], theta[A], theta[B], theta[AB]), theta[A])+diff(f(theta[I], theta[A], theta[B], theta[AB]), theta[B]);

pdsolve(PDE[1] = 0)  ----->  f(theta[I], theta[A], theta[B], theta[AB]) = _F1(theta[I], theta[A], theta[B])

pdsolve(PDE[2] = 0) ----->  f(theta[I], theta[A], theta[B], theta[AB]) = _F1(theta[I]+theta[A], theta[I]+theta[B], theta[AB])

pdsolve({seq(PDE[i] = 0, i = 1 .. 2)}) ---->  Error, (in PDEtools:-casesplit) too many levels of recursion

Why doesn't it produce the answer, although I know that it must be:

f(theta[I], theta[A], theta[B], theta[AB])=_F1(theta[I]+theta[A], theta[I]+theta[B])

Hello,

I have a function:

v0(t) = -g*t-vs*ln(r*t-m0)+vs*ln(-m0)

This function should be equal to 300, but when using fsolve we get a negative real part, and a very small imaginary part:

We have already made a plot of the function, and from that we see that the t should be about 65 when v0(t)= 300.

What are we doing wrong?

Is there a way to extract the data from the graph?

There is an example in the help of maple, that is to solve the symmetries of the equation ut=uxx using the order "Infinitesimals".

But the result i can't understand.

I solved by hand and find  _eta[u](x, t, u)=cu+b(x,t), where b(x,t) is a solution of the ut=uxx.

While in maple, b is only two exponential function which are also the solution of ut=uxx. 

why?

thanks for your help!

hi..i have a problem for solving this nonlinear differential equationerror.mw

Download error.mw

please help me

thanks...

How do I insert Maple18 plots into LaTeX documents?

How to evaluate a Stieltjes integral ?  I'm not asking for the definition of the Stieltjes integral, I want to know how I can get maple to evaluate one.

I am having trouble with understanding how to use piecewise to define a function f such that

f(x) = 1 whenever the VALUE of x is an integer (thus f((2^(0.5) - 1.0)*(2^(0.5) + 1.0)) = 1).

f(x) = 0 otherwise.

I had problems plotting the solutions of my PDE with the derivative as the axis. Anyone knows what went wrong?

p1 := pds:-plot(diff(f(x,y),y), y = 0 .. 10, x = 0, numpoints = 100)

I seem to be getting a plot of y=0. Any help would be greatly appreciated:))

fyp2.mw

The angle unit of the SI system is rad and its dimension is 1. In engineering angles are often scaled in degrees. Maple supports the unit "deg" or "arcdeg". However when calculating with these units it does not convert deg to rad automatically and replace rad by 1. Here is an example:

The result of evalf(B) should be 15.708 (= 5*pi), i.e. a value without dimension, neither arcdeg nor rad. How do I get the correct result?

I need to write a procedure that adds all multiples of 5 and 7 less than an arbitrary number. I was thinking something maybe with mod? I am very new to Maple. 

On in this same assignment, we are also supposed to generate a sequence using the Fibonacci equation but from an arbitrary pair of initial conditions. So if there are some parallels between these two problems, I would love to learn from that angle.  

We recently in class learned about do loops, so if there is a way to attack these problems with do loops, I would like to hear!

Hello,

I have to solve numerical trogonometric equations such as :
solve(.3707752782+.1499320455*sin(theta[4](t))+.1117559025*cos(theta[4](t))=0.5,theta[4](t));

But, after, I would like to keep only the solution defined in a specific interval such as : [0,Pi]

1) Is there a possibility to define options with the function solve to limit the solutions belonging to a specific interval ?

2) Otherwise, may you help me to make an systematic process to choose a solution in a specific interval ?

Thank you for your help

I need to change the following continued fractions into rational numbers using the cfrac function:

1)  [1 , 2]               2) [1, 1, 2]                3) [1, 1, ,1, 2]

Thanks,

Sara

I know there is some code to compute the symmetry of pde, but i want to compute the symmetry of some differential expression, as f(x,t,ux,ut).

The difference is that when solve the infinitesimal, we don't have the identity f(x,t,ux,ut)=0, we just take each variable in the jet space as independent.

Is there any package to do that?

help and thanks!

Greetings,

I have been attempting to plot a couple of functions and I keep getting the same error.  I will copying and paste what I have entered and the error messages

with(plots);

with(VectorCalculus);

sphereplot*(rho = theta, theta = 0 .. 4*Pi, phi = 0 .. (1/2)*Pi);

Error, (in simpl/reloprod) invalid terms in product: (rho = theta)*(theta = 0 .. 4*Pi)

with(plots);
with(VectorCalculus);
fieldplot*(<-x, y, cos z>, x = 0 .. 5, y = 0 .. 5, z = 0 .. 2*Pi);
Error, (in simpl/reloprod) invalid terms in product: (x = 0 .. 5)*(y = 0 .. 5)

Any assistance would be most appreciated.  Thanks in advance.

Hello,

how can I use procedures saved in ".m" files in my own repository?

I've created

LibraryTools:-ShowContents("C:\\Users\\Stefan\\maple\\toolbox\\myfactor\\lib");
[["Auxiliary.m", [2016, 10, 10, 15, 53, 20], 1024, 3333]]

and registered it in the maple.ini
libname;
     "C:\Program Files\Maple 18\Maple 18\lib",
       "C:\Users\Stefan\maple\toolbox\Iterator\lib", ".",
       "C:\Users\Stefan\maple\toolbox\myfactor\lib"

but Maple don't know the procedure squarefree() from the repository. What is wrong?

Thanks