Today I try to solve a simple ODE: dot{x(t)}=sin(x(t)). Maple gives me the below answer:
x(t) = arctan(2*exp(t)*_C1/(1+exp(2*t)*_C1^2), (-exp(2*t)*_C1^2+1)/(1+exp(2*t)*_C1^2))
How comes the arctan function takes two arguments?
I solved the equation by myself, and a simple manipulation result in the follwoing result:
x(t)=2arctan(C*exp(t))
How can maple end by a 2-argument arctan function?? Help...

Suppose you want to sort a list L ( of numbers ) and also determine order of elements as a list of indices corresponding to elements of original list L, that is, you want such a integer list "I" that

`"seq(L[I[j],j=1..nops(L))"`

to be equivalent to sorted list. This functionality is present in MATLAB in

`"[B,IX] = sort(...)"`

syntax and i come up with this problem while trying to convert a MATLAB function (

GaussQuadratureWeights) to maple. The procedure described resolves problem using a few MAPLE commands including MAPLE's built-in sort function.

Hi, All,

Please see below:

> restart:

> with(DEtools):

> deq := diff(y(x),x,x) = A*exp(y(x)/vt);

> deq2 := diff(y(x),x,x) = A2*exp(y(x));

> #y := unapply(rhs(dsolve(deq,y(x))),x);

> y2 := unapply(rhs(dsolve(deq2,y(x))),x);

If I let two dsolve go, it gives error message for the second. However, commenting one and letting one go will always works perfectly. What's the problem, any bugs inside Maple. I tried in Classic Maple and Maple 10. same problem happend.

Thanks.

David

Yes they do but it is still very much a community driven site. Maplesoft staff are free to contribute but we do not have dedicated staff other than the the group that manages the site function itself. See

here for more comments.

This is more of a question than a suggestion.
My experiences with this site have all been positive, and I'm extremely grateful for the wonderful service provided by the staff members.
I understand that a lot of the questions posted sometimes require a good deal of time and effort to answer.
However I'd like to know why some "Newbie Questions" are answered only after hours, and some after a few days ?
Is there a system or is it just the luck of the draw ?
It also seems like there are a few staff members on this site to handle this heavy load.
My question / suggestion is whether or not there is some possible way to address this issue, and if this issue is actually being addressed currently ?

Consider the task of sorting a list of complex floating-point numbers by magnitude.

**First Attempt**
The usual method to do this in Maple is with the

**sort** procedure. By passing a boolean-valued function that computes then compares the magnitudes of two complex numbers, we can sort the list. The following procedure shows how this is accomplished.

sort1 := proc(L)
return sort(L, proc(z1,z2) abs(z1) <= abs(z2) end proc);
end proc:

A disadvantage of this approach is that the absolute-value procedure is called twice every time a pair of numbers is compared. For a long list, the time spent in the absolute value routine dominates the computation time.

One of the joys of the software biz is the total uncertainty of things. We learned that the hard way last week when the course of regular maintenance on the servers took a horrible, nasty turn ... the great news is we're back with a brand new, high-performance server, and have switched over to SuSE Linux as the O/S. We're optimistic that we now have the proper infrastructure to sustain growth in this site ... and to also hook up some interesting new features that we have planned for the near future ... stay tuned.

MaplePrimes was down for a while this morning ... our appologies. Just to let you know, we are moving the site to a brand spanking new HP server blade within a few days. The site has reached a critical mass that we need to ensure greater reliabily and we're taking the step (hardware and humanware) to do this. Thanks for your patience. T4.

Thanks to Roman Pearce for this suggestion for the new poll. This topic is one of the livlier debates within the Maple community. Please indicate which platform you use for your Maple work.

I have now identified where the problem is in the plotting of unduloids using elliptic functions. There seem to be some singularities arising in Maple 10 that were not there in earlier Maple versions. I noticed also that, on the functionadvisor help page for EllipticE, the branch points are listed differently. Maple 9.5 has ... k, 1/k and Maple 10 has ... -1/k,1/k ... Is this a misprint or the source of the trouble. At any rate, for those who want to see what is happening, try the following in Maple 9.5 and in Maple 10:

**> **

FYI: Maplesoft just released

DynaflexPro , a new product that generates equations of motion for physical systems (including mechanical, mechatronic, and others). Automatic generation of model equations is one of the most powerful and popular applications of Maple in the engineering fields and Dynaflex offers a lot of tools to make this more efficient.

A colleague has been frustrated by the apparent limitations to Maple's abilities to "solve" inequalities. This does appear to be something that should - and could - be improved with a little effort.
The typical problem under consideration is the epsilon-delta definition of limit. Ideally, it would be nice to execute a command such as

> solve( abs( f-L ) < epsilon, x );

and receive an answer in terms of intervals.

I have a classic-worksheet version of Maple 9.5 that runs as an X11 application on my Macintosh. Is there a classic-worksheet version of Maple 10 that does the same? If so, where can I get it?

It would be good if I could tell looking at the list of messages in the Inbox or other folder, to which of them I replied. Also, it would be a nice feature if I could see in the Sent folder whether my message to somebody had been read, or not.