i study a simple differential equations as follow and get the solution,but i faced two warning which puzzle me:

> restart;
> eq2 := diff(x(t), t) = x(t), diff(y(t), t) = x(t)^2+y(t)^2-1;
   ans1 := dsolve({eq2, x(0) = 1, y(0) = -1}, numeric, [x(t), y(t)], range = -10 .. 10)       ;

Warning, cannot evaluate the solution further left of -1.1646698, probably a singularity

Just a small digression.  It would be nice if the numbers on the x-axis could be rotated or angled so it does not look like they collide with each other.  When the numbers reach the 100's or 1000's there will be congestion. 

This is perhaps a suggestion for a future Maple version as the current versions do not support number rotations on the axis.

Hi everyone,

I have this differential equations:

gamma1:=1;gamma2:=1;

l:=t->sqrt((x1(t)-x2(t))**2+(y1(t)-y2(t))**2);
2 2
l := t -> sqrt((x1(t) - x2(t)) + (y1(t) - y2(t)) )

DE:=[diff(x1(t),t)=(-1/(2*Pi))*gamma2*(y1(t)-y2(t))/l(t),diff(y1(t),t)=(-1/(2*Pi))*gamma1*(x1(t)-x2(t))/l(t),diff(x2(t),t)=(-1/(2*Pi))*gamma2*(y2(t)-y1(t))/l(t),diff(y2(t),t)=(-1/(2*Pi))*gamma1*(x2(t)-x1(t))/l(t)]:

I want to draw the phase portraits (x1(t...

Dear everyone,

  Hi,

  I have a simple problem of writting data into a file:

  For something like

***********

for i from 1 to 3 do
  L[i]:=i;
end do;
writedata(`d:\test.txt`,L);

***********

I got
                       ...

Hello,

Just a small question: what's the difference between writing

product( (2*i-1) mod 3 + 1, i=1..10 )

which incorrectly gives 105411381075, and writing

mul( (2*i-1) mod 3 + 1, i=1..10 )

which correctly gives 432...

And what's the reasoning behind this?

-- Regards,

Franky

Hi everyone,

While I am getting more and more comfortable with the document mode, I have some questions regarding the document block feature:

- What is a document block good for anyway?
- Why not have the whole document in one block?
- Can one join two document blocks?
- when do I "remove the document block"
- How can I make sure that say an informational 2-D math expression inside a document block never gets executed?
-- Can I still...

The Locator object is a nice piece of Mathematica's Manipulate command's functionality. Perhaps Maple's Explore command could do something as good.

Here below is a roughly laid out example, as a Worksheet. Of course, this is not...

I write this code:

> e1 := a-3;
                             a - 3
> e2 := sqrt(6)*b+6;
                           (1/2)      
                          6      b + 6
> trac := e1+e2;
                                 (1/2)  
                        a + 3 + 6      b
> dter := e1*e2;
                             / (1/2)      \
                     (a - 3) \6      b + 6/
> dell := trac^2-4*dter;
                           2                           

Hello, I'm just starting to work with maple I'm working on Enzyme kinetics project and I have no idea how to solve ODE system using GEAR'S or A-stability methods. I'm looking for help.

What is wrong?

> restart;
> Digits := 10;
> dsys := {diff(E(t), t) = -kf*E(t)*S(t)+kr*ES(t)+kcat*ES(t),

Hi, I'm trying to calculate a few integrations:

E1:=map(int(N1),eta=eta0..eta2)

E2:=map(int(N2),eat=eat0..eta2)

E3:=map(int(N3),eta=eta0..eta2)

N1, N2, and N3 are 3x3 matrix are are functions of eta0, eta2. eta0 and eta2 are derived after several integration as well.

If i do not want to change the name "eta0" and "eta2", can i write something to indicate (eta0 for E1 is 8.3, eta0 for E2 is 4.5, eta0 for E3 is 7.9). I hope...

Hi,

given a ploynomial in three variables x,y,z, I want to check if it is nonnegative for all (x,y,z) in R^3.

I know there is a function 'verify' in maple but it doesn't work with my polynomial, I think it's too complex.

Do you have any idea which other function I could try?

Thank you

flower15

Hi, i'm trying to change Matrix([[9,8,7],[6,5,4],[3,2,1]]) into Matrix([[1,2,3],[4,5,6],[7,8,9]]). I try to use FlipDimension, it works with two steps, but i cant seem to fit it into one step. Is there a simplier thing that i could do please? Thanks.

Hi,

i've been using evalf(Pi*5.6) for my calculations. after a few steps of calculations, some of the values are as small as 7.4x10^-9 . These small values are insignificant to my calculations. how should i ask maple to ignore all the positive and negative values that are smaller than 1x10^-9?

Please advice. Thanks