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I have a set of PDEs & I tried to solve it. First of all I defined some functions as:
H := (diff(a(t, y), t))/a(t, y), Hy := (diff(a(t, y), y))/a(t, y), H1 := diff(H(t, y), t), a1 := diff(a(t, y), t), a2 := diff(a1, t), Hy1 := diff(Hy(t, y), y), ay1 := diff(a(t, y), y), ay2 := diff(ay1, y), n1 := diff(n(t, y), t), n2 := diff(n1, t), ny1 := diff(n(t, y), y), ny2 := diff(ny1, y), pef := -2*n(t, y)^2*Hy1-3*n(t, y)^2*Hy^2-n(t, y)*ny2-2*n(t, y)*Hy*ny1-2*H(t, y)*n1/n(t, y), `ρef` := 3*n(t, y)^2*Hy1+6*n(t, y)^2*Hy^2, `ωef` := pef/`ρef`,

Hi every body I have two functions which are aold(x) and anew(x). I am using them to update a function as: For example: aold:=x-> x^2; for i from1 to 5 do anew:=x->aold(x)+x; aold(x):=anew; end do; But it does not work because it cause loop in assigning the function. Also, if I unassign the aold(x) as aold(x):='aold(x)', also anew(x) got unassigned automatically. I am looking for a way to assign anew(x) as anew(x)=aold(x) and after that disconnect the relation between the two functions. Thanks Hamidreza.

I need to find value of integrals ratio:


where the functions f1(t), f2(t) are result of numerical solution of differential equations system:

> restart; with(plots):
> sys:=diff(f1(t),t)=piecewise(t<=4,3*exp(-2*t),-1),
init:= f1(0)=1, f2(0)=1:
> F:=dsolve({sys,init}, {f1(t), f2(t)}, numeric);
> Result:=odeplot(F, [[t,f1(t)],[t,f2(t)]], 0..5.5):
> display(Result);

Hi there!

Suppose I have an expression

Expr:=a*f(x[0],...) + b*f(x[1],...) + c*f(x[2],...),  

where the ellipses represent (different) functions of x[0]..x[2]. I'd like to use frontend to get the coefficients a, b, c corresponding to x[0], x[1] and x[2]. If the function f only has one argument, that's peanuts:

Hi.  I want to plot the function U in terms of x and y,

U :=2*diff(p(x,t),x)*diff(q(y,t),y)/(p(x,t) + q(y,t) + a[0])^2;


<p>Hi </p>
<p>I have some funtio<img alt="" src="file:///C:/Users/BrianBak/AppData/Local/Temp/moz-screenshot-5.png" />ns that a generate using maple. I would like to be able to set an variable equal to the right side of these functions in matlab. I have saved the funktion in the following way. </p>
<p><img alt="" src="file:///C:/Users/BrianBak/AppData/Local/Temp/moz-screenshot-6.png" /><img alt="" src="file:///C:/Users/BrianBak/AppData/Local/Temp/moz-screenshot-7.png" /><maple>with(CodeGeneration)</maple><br />
<maple>Matlab(x^2+y^3, output = "file.txt")</maple></p>


I defined the following functions:



I've performed the exact same calculation (using the exact same worksheet, with absolutely no changes made) last night and today and got these results:

y=[0, .4646313991, .9499094532, .5799050874, .1092604065, .4031507404, .8483735670, .6138799333, .1913933456, .3724618402, .7707837830];

y=[0, .4646313991, .9499094532, .5799050874, .1092604061, .4031507404, .8483735643, .6138799354, .1913933461, .3724618343, .7707837938];


Which are exactly the same modulo the last 3 digits.

Digits=10 in both cases.

Hello! I have a problem - i can't find standart Maple functions and procedures, that plot, so to speak, "phase portrait"-esque magnetic field lines for featured "vector field". In details: i need to plot magnetic field lines and equipotential curves of uniformly magnetized cylinder. I have piecewise functions Hr(r,z) and Hz(r,z), (per se, r is x, z is y, y-axis coincides with cylinder axis): L := 2; a := .5


I read data into Maple, and based upon that, wish to dynamically construct a piecewise function. In advance, it is unknown how many entries the piecewise will have or where the breakpoints are.

How can I work dynamically/programmatically with piecewise functions? Is there some documentation or concept I should know about so I can help myself on this? The only possibility I've found thus far is using the sscanf function, which makes it a little more complicated than necessary.

Hi all, Being new to Maple, I have a rather trivial question for most out there. How does one plot x=ln(y) or any function x=g(y) to be more general? I have worked with implicitplot() as such, but it only feels like drawing a straight line for x=ln(y). Here is the syntax I used: > g := y -> ln(y) > with(plots) > implicitplot(g, x = -10 .. 10, y = -10 .. 10) Does maple expect the assignment of the full equation (i.e. g:= x = ln(y)) in order to process inverse or implicit functions? I'm obviously borking the syntax. I have searched through this forum and the help. Any information is thoroughly appreciated in advance. Phillip

about Poincaré conjecture brifely described :

since there is a lots of  mathematican in this nice forum , I think the discovery of Grigori Perelman is very hot subject for discussion ...

personaly i am so eager to know why he is the only one that could solve the problem ? and also what is the application and effect of this success ( maybe future ) ?

Hi (working with maple since yesterday, so question might be elementary) I have an ODE system with functions x(t,k),y(t,k), t is the independent variable, k is a parameter, as well as initial conditions. What I am aiming at is a 3-d plot of the _derivate_ d/dt x(t,k) of the first solution of the system, and t and k as horizontal axes.
Hi. I recently turned over to maple 13, after using TI InterActive! for 2 years. But i am having som problems working with vector functions in maple. Here is a link to the PDF file with the exercise in TI: It's when i reach "Opgave 2d" that i get into trouble.. when i differentiate the r(t) function it just gives me an error.. "non-algebraic expressions cannot be differentiated" And im just wondering wether there are other functions in maple to differentiate vector functions?

Hello there.

I´m fairly new to maple, so i apologize if this is a rather "simple" question, but right now I don´t really know how to get rid of the error message that occurs.

What I try to do is define 3 components of (in this case) a function that describes a magnetic field. These functions ( seen below) depend on a few parameters (a,b,c,d,p and chi).


> PlotMfield := proc (a::float, b::float, c::float, d::float, p::float, chi::float)

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