Bonjour,

J'ai une erreur lorsque j'essaie de résoudre un système d'équation différentielle : "Error, (in DEtools/convertsys) unable to convert to an explicit first-order system" et lorsque je simplifie le système j'ai une erreur : "Error, (in dsolve/numeric/DAE/checkconstraints) the initial conditions do not satisfy the algebraic constraints".

Merci d'avance pour votre aide

Hi

During a longish run (memory usage gets to about 1815M in 583s ) the loop terminates with the error message

" Kernel connection lost

Hi everybody,

I've got a numerically computed 2D free energy profile given by a set of 3D points (x_n,y_n,E(x_n,y_n)). I'd like to obtain a fit to those points given by some sufficiently smooth analytical function E(x,y) and subsequently compute the critical points (i.e. local minima, maxima and saddle points). Does anyone know if there is any specific package to do this in Maple 8 (or higher) or else what is the best strategy to do so? Thanks in advance.

Dear  Maple World members,

I have a problem and I do not know how to solve this equation with Maple. If anyone can help me, that will a huge gift for me :)

{ [ dy/d(t) ]  / [ dx/d(t) ] } = e*[  ( a + b* y(t) + c* x(t) + d* x(t)* y(t)+ f *y(t)^2 )  / ( a + b*x(t) + c*y(t) + d* x(t)*y(t) + f* x(t)^2 ) ]

initial conditions :

at   t = 0,   x(0) = Xo, y(0) = Yo

Hi, i have the following equation system, for which i  already know the solution.

restart:

s1:=(r1*r2-1/(400000000*c1*c2))*(r1+r2)/((r1+r2)^2+(-1/(20000*c1)-1/(20000*c2))^2)
+(-1/20000/c1*r2-1/20000*r1/c2)*(-1/(20000*c1)-1/(20000*c2))/((r1+r2)^2+
(-1/(20000*c1)-1/(20000*c2))^2) = 611.0987791:

s2:=(-1/40000/c1*r2-1/40000*r1/c2)*(r1+r2)/((r1+r2)^2+(-1/(40000*c1)
-1/(40000*c2))^2)-(r1*r2-1/(1600000000*c1*c2))*(-1/(40000*c1)-
1/(40000*c2))/((r1+r2)^2+(-1/(40000*c1)-1/(40000*c2))^2) = -8334.070796:

In Maple 11, using labeldirections = [horizontal,vertical] was enough to display the y-axis label vertically.

But in the Maple 12 version this no longer changes the label to vertical, it still displays as horizontal and just cuts off the remainder of the label.

Has there been a notation change?  How can I now display the label vertically in the new Maple 12?  Thanks.

How do I put a number, as an example: 987654321 so that all the digits are in a list?  Say I want to pull out the 7th digit, which in this example happens to be 3.  Or let's say I want to find out what the 473rd digit in Pi is.

it would be of a great help if anyone share the companion CD of

I have a set of 2nd order nonlinear differential equations which I solve numerically. 

odeplot plots the numeric results of the function and first derivatives just fine.

I was wondering if there is anyway to plot second derivatives.

odeplot treats a 2nd derivative as zero.

Although, I don't know  for sure, I believe the RKF45 routine computes them during the integration. Any way to store them?

Any ideas are appreciated.

Thanks

I have two differrential equations:

1) x ' ( t ) = x( t ) + y( t )

which can be written as

x ( t ) - x (t -1) = x ( t) + y (t )

- x (t -1) = x ( t) + y (t ) - x ( t )

- x (t -1) =  y (t )           A

2) y ' ( t ) = 4 * x( t )  + y (t )

which can be written as

y( t ) - y (t -1) = 4 * x( t )  + y (t )

y( t ) = 4 * x( t )  + y (t ) +  y (t -1)        B

Hi there.
I've been having difficulties figuring out how to make Maple update my plots when I use for example the scale axes tool, so it doesn't just stay at a default range of [-10;10] but instead updates to fill out the whole screen.

Hello,

First of all I would like to thank Joe Riel and congratulate him for the great maplev mode for emacs.
If any of you use it I would appreciate a little help with running "mint" from emacs.

Here's what the maplev specific part of my .emacs looks like,

When I want to simulate and plot the distribution from a random coin toss (normal distribution) I use the following code:

restart:
randomize():
coin:=rand(0..1):
coin_1:=proc(n) seq(coin(),i=1..n) end:
x_1:=seq([coin_1(10)],i=1..500):
x_2:=[seq(numboccur(1,x_1[i]),i=1..500)]:
with(Statistics):
Histogram(x_2,frequencyscale=relative,discrete = true );

what code should I use in order to get a coin with serial correlation. A normal distribution with fat tails? (Prefereably I want to tweak the above code)

Due to a do... for cycle I obtain thes data:

....