I'm trying to solve a system of equations in maple and I have no idea why it's doing what it's doing but it certainly isn't working. Anybody have an idea what's going on?

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i have a problem of my equation with differentiation,in the first i run it total OK ,but when i input the value into the equation, the ERROR was show the screen.
i don't know which step have the problem in my procedure.
under is my maple file,(if you can't understand what mean of this procedure,just send me E-mail).
regards

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A colleague asked me about this, and I couldn't help him:
```
> g:=y+exp(2*t):
> y2:=subs([y=3,t=0.1],g);
y2 := 4.221402758
> subs([y=y2,t=0.1],g);
4.221402758
```

Why has not the new value of y2 been substituted for y in this last expression? And the same thing happens for eval.
Thanks,
Alasdair

I've already found the commando's logplot and loglogplot on my own. The first defines a log scale for the y axe. The second defines a log scale for both the axes.
Now is my question where could I find the command for plotting a log scale for the x axe.
I suspect it is something special because I could not find it in the library plots.
My excuses for my terrible English!
Greetz Pieter

I am trying to write a paper in which I can, for presentation purposes, collapse document blocks and have the code not shown. I am running into the problem that when I collapse some document blocks code within is not displayed but when I collpase other document blocks all that goes away is the red prompt. I can't figure out why the difference. The attached file has two document blocks which, as far as I can tell, are identical except for a few words of text. When I collpase the first block the code remains displayed, but when I collapse the second block it does not. Can anyone figure out why the difference?

Hello,
I'm wondering if it is possible to produce a composite plot in Maple. What I would like to do is:
1. Take one solution of a non-autonomous differential equation, and plot it with respect to t, call this x(t).
2. Take another solution of a similar equation, also plot it with respect to t, call this y(t).
3. Take x(t) vs. t and y(t) vs. t planes and use it to create a 3-dimensional plot containing all the points where (t,x(t))=(t,y(t)).
It's difficult to describe, I hope the above is helpful.
On a (hopefully) simpler note, when I solve the following:
odesys := diff(x(t), t) = 2*x(t)-y(t)-x(t)^3, diff(y(t), t) = x(t)

hi there...
im trying to plot this equation onto a graph-
x-2y=4
x+2y=12
I dont knw how to put it into maple.....as maple only reads one equation at a time and not as a whole????
help please....

Tried to maximize a simple function f(t), failed.
Converted it to different forms, still failed.
Simplified the function a bit by hand and tried again, still fail.
Only after some major simplification by hand
and a transformation: u=s^2=(1/2-t)^2,
it finally worked.
I must be missing something.
I thought such a simple problem should certainly be solved by maple in a flash.
Can someone enlighten me please?
Thanks a lot.
> maximize(t^2*(1-t)^2*(1+t^2)*(1+(1-t)^2), t = 0 .. 1);
/ 2 2 / 2\ / 2\ \
maximize\t (1 - t) \1 + t / \1 + (1 - t) /, t = 0 .. 1/

Question is easy but not for me :). How do I convert fractures into regular numbers. Thank you!
Greetz Pieter

Hi
Please see Spiderflygrid2.mws
A spider is on the floor of a cubical room of side 1. Its position is given. Where must the fly position itself to be as far as possible from the spider?
My attempt minimizes the square of the twelve possible distances. This is m.
m:=min(seq(cd[i], i=1..12));
Partial derivatives of m are found with respect to xf (the x coord of the fly)
eq1:=diff(m,xf);
... & with respect to yf (the y coord of the fly)
eq2:=diff(m,yf);
These two equations are then solved simultaneously.
solve({eq1,eq2});
Maple gives an error message - is this due to the discontinuities in the expression m? Or (more likely) a fault in my Maple code?

Hello - this is a novice's question: Consider the following:
> E1 := a = b
> E2 := b = c
> eliminate({E1, E2}, {b})
[{b = c}, {a - c}]
So this works.
> E3 := a1(t) = b1(t)
> E4 := b1(t) = c1(t)
> eliminate({E3, E4}, {b1})
Error, (in eliminate/recursive) invalid subscript selector
What should I do in the second set above to eliminate b1(t) and get the result a1(t) = c1(t)?
Thanks.

I'm numerically solving, using pdsolve on Maple 9, the diffusion-recombination equation. I'm interested in the long time behavior after a very short time excitation pulse. Ideally, pdsolve would have the capability to use a small time step for the initial part followed by a larger time step later. Otherwise, I could take the result of a calculation with a short time step as an initial condition for a calculation with a long time step. If anyone knows how to do either of those things, I would be grateful.
Thanks,
Richard

I have Maple 10.04 running on my PC. The Maplesoft product update site says Maple 10.06 update is available. Do I have to install 10.05 update first? Or can I go from 10.04 to 10.06 directly?? Thanks in advance !

Hello everybody
I need to draw a phase portrait for the one-dimensional linear independent equation(just the arrows in axe X)
Help me, please!!!

> Suppose I create a matrix as follows:

**> **

Now I want to make it a 4 x 3 matrix by adding a specific row vector on top. The approach below doesn't work.

**> **