First of all: I'm so sorry, I posted my question to a wrong place ( into the poll).

So I copy here the question and the answer of jakubi and my reply to jakubi.

**Question**:

I would like to solve the following system

x*(2*sin(x)*y^2+x^3*cos(x)+x*cos(x)*y^2) = y*(2*sin(y)*x^2+y*cos(y)*x^2+y^3*cos(y)),

-x*sin(x) = y*sin(y);

Until I have founded only the solutions

x = k*Pi, y = +/- k*Pi; k is any integer.

**jakubi**'s answer:

more solutions

Hello every body, and many thanks for our help !!!

i have the following transient heat conduction equation:

dT/dt = a * d^2T/dx^2

now i have:

T(0,t ) = k1(t) : boundary condition

T(L,t) = k2(t) : boundary condtion

T(x,0) = k3(x) : initial condition

and

T(x,t) : solution at all the time

how to find out

a ?

I need to plot the slope field for this DE:
(y'(x))^2 - 4*x*(y'(x)) + 4*y(x) = 0
I'm very new to Maple (tonight was my first time using it) and I'm not a good programmer, so any light you can shed on my problems would be much appreciated.
This is what I tried:
> with(DEtools);
> eq := (diff(y(x), x))^2-4*x*(diff(y(x), x))+4*y(x) = 0;
> DEplot(eq, y(x), x = -1 .. 1, y = -1 .. 5);
And then I get this error:
Error, (in DEtools/DEplot/CheckDE) unable to isolate DEs for required derivatives
Thanks

November 04 2009
lena 56
The fubction I've got for ex:

f(x,y)= sum(exp(x*r[i])*a(r[i]),i=1..3):

where:

r[1],r[2],r[3] are functionsof y

I plot f in 3d in the case when r[i] are values. no problem

but i got confused when r[i] are functions

work with literal subscript. desire to isolate theta [B]. I show in the picture what the steps in Malpas and their outputs. With the last option Maple returns nothing.

Hi,
I'm trying to solve a non-linear difference equation numerically, but I receive following error:
**"Error, (in DEtools/convertsys) unable to convert to an explicit first-order system"**
I filtered the essential parts out of my code:
`a:=t->T(t)/m(t)-G0*m_aarde/(R_aarde+y(t))^2;`

ss:=dsolve({Diff(y(t),t,t)=a(t),y(t0)=0,diff(y(t),t)(0)=0},{y(t)},numeric,method=gear,output=array([seq(k,k=1..astappen)]));

Hi

I don't find how to assume that the codomain of a function is the real range (0,infinity)

I want to define g:= h-> A(h) and tell to maple that A(h) (or g(h) which is the same) is real for each h, even if the function A is still unknown.

Aditionally I can't undestand why I obtain

restart:

I am studying the application file "Maple in Finance" www.maplesoft.com/applications/view.aspx

I have posted some of the stuff below. I have a hard time following along with the reasoning.

Could anyone please explain what is going one here is simple words ?! There are a lot of new stuff here.

Hi

im working with a complicated system of equations and am tryin to find steady states, ive set the equations equal to zero and isolated a particular variable, i now want to sub this variable back into another equation, is there a way i can use the isolated variable without copying the answer and pasting it into 'subs'? (the experssion for the variable is very long and messy!)

Thanks!

How can I get Maple 10 Standard Worksheet to plot with vertical logarithmic axis having the gridlines at 10,10, and so on, in a **vector graphic** file like eps?

I am trying to maximize a concave function and I have 6 different parameters. I use the maximize command and establish the relevant constraints. The result I obtain is numerical, but I would like to have an analytical solution with one of these parameters being the dependent variable as a function of the others.

Can I use the maximize command or any other command that will give me an analytical solution instead of a numerical one?

Thanks.

How to execute expression when creating a function?

(before creating it, inside it)

Hello,

I'm having a bit of difficulty with the function "eval" I would like it to perform a full evaluation of an expression, but it does not appear to be doing this. When I try to explicitly pass it a value for the evaluation level it doesn't appear to take the integer input, the only way I can get it to work is to nest calls to eval ...[ie eval(eval(exp))]. Below is the code giving me the problem, the problem occurs on the last line...any suggestions would be appreciated

Thank you.

with(plots):

contourplot(-z*(1/(x^2+z^2)^(3/2)-1),x=-3..3,z=-3..3,grid=[50,50],contours=10);

Doesn't seem like maple is plotting enough point for a nice smooth rounded graph. Can I smooth them to look more realistic?