## 112 Reputation

13 years, 355 days

## Dear Mathematicians , May I...

Dear Mathematicians ,

May I get any help for the above mentioned problem please ?

## Dear Robert Israel, I am...

Dear Robert Israel,

I am not amthematician and I can not really understand these concepts, I have never used  LSSolve,

may I request you that you solve this numerically for me please, and plot it.

that will be very very graceful

thanks, greets

poor Ironmoon :(((

## Dear Israel,   yes  this...

Dear Israel,

yes  this equation  reduces into what you have shown, now we can take this equation into account and use it for the rest of problem :)

It is for me very  complicated  since I look for different solution

for example

question 1) if b=e=0

how can I solve this equation and how can I find a, c  with the given data set ( I mean how can I simulate it with maple )

question 2)

if b and e are not zero what can be the solution

## Dear Robert ISrael, un the...

Dear Robert ISrael,

un the   new defined parameters,  K= b/a = e/c = X / M =  Y/ R

the ratio of time dependent  X(t)/ M/t) and Y(t)/R/t)  are constant, but this is just an information, it may not be used in the solution.

Perhaps it is better  solve this problem stepwise.

1-

X(t)=  Xo- M(t);   >  M/t) = Xo-X(t)

Y(t)= Yo - R(t) ; > R(t)= Yo - Y(t)

N(t)= M(t) + R(t);  > N(T)  = Xo - x(t)  + Yo - Y(t)

Z(t)= Zo - M(t) - R(t) ;   >  Z(t) = Zo - Xo- + X(t) - Yo + Y(t)

new defined parameters,  K= b/a = e/c

E= a / c

Let us substitute    X(t), Y(t)  and  M(t) in x ,  N(t) in Y

ODE functions are system ODE  for simultaneous solution

dX/ dt = b.M(t). N(t) - a. X(t). Z(t)

dY/ dt = e. R(t). N(t) - c. Y(t). Z(t)

dX/dY = [ b: M(t): N(t) - a. X(t). Z(t) ]   /   [ e.R(t). N(t) - c.Y(t). Z(t) ]

---------------------------------

is it

possible to find  E= a / c =  after solvung this new ODE

thank you

## A silly question...

Dear Robert Israel,

Y(t)

X(t)   are different functions but effect each other, so should it be two different separate

Y vs. t   and  X vs. t    curves on the same  2 D coordiantes  ?

greets

AA /  Germany

## Dear Robert Israel, thank...

Dear Robert Israel,

thank you sooooo much for your approach, now I try to understand them all. I wish I had been a mathematician and also good at maple :(((((

May I send you experimental real values if you still want to help me?

thanks

AA

## Thank you very much...

Dear Robert Israel,

I am very thankful to all who worked for this problem. I now got :) that the closed forms have no soln.

If I have a data set of

t                               x(t)                                        y(t)

0                               1                                             1

1                                 0.9                                      0.8

2                                0.8                                       0.5

and so on,

how can it be possible to to simulate

[ dy/dt ]  = m ( a + b* y(t) + c* x(t) + d* x(t)* y(t)+ f *y(t)^2 )

[ dx/dt ] = n  ( a + b*x(t) + c*y(t) + d* x(t)*y(t) + f* x(t)^2 )

both equations simultaneously to detect the values of the coefficients ?

sorry for my foolish questions, but I need them :(

thanks soooooo much

AA / Germany

## Dear Alec,  sorry in...

Dear Alec,

sorry in previous message, so has been son :)

anyway, I applied your suggestion and waited more than a hour, nothing came out :(((((

do not know how long one can wait to understand if maple has a solution.  For coefficients, unfortunately they are physically existing therefore I can not make them zero...

I have two questions, if you still want to help me.

a) in this above -equation, ( e  ) value should be detected as ratio of  y and x , how can I make numerical solution if dy/dx also exits in the equation ? or

b) how can I  solve system, analytical or numerical :((((  ?

[ dy/dt ]  = m ( a + b* y(t) + c* x(t) + d* x(t)* y(t)+ f *y(t)^2 )

[ dx/dt ] = n  ( a + b*x(t) + c*y(t) + d* x(t)*y(t) + f* x(t)^2 )

in previous Abel's 2nd type   ,  e = m/n

initial conditions :

at   t = 0,   x(0) = Xo, y(0) = Yo

simultaneously :(((

thank you very much

AA / Germany

## no result :(...

Dear Alec,

sorry in previous message, so has been son :) anyway, I appled your suggestion and waited more than a hour, nothing came out :(((((  I do not know how long one can wait to understand if maple has a solution.  For coefficients, unfortunately they are physically exiting therefore I can not make them zero...

I have another queation, if you still want to help me.

in this equation, e value should be detected as ratio of  y and x , how can I make numerical solution if dy/dx also exits in the equation ? or how can I  solve system

dy/dt = f( y,x)

dx/dt:f(y,x)

simultaneously :(((

thank you very much

AA / Germany

## no result...

Dear Alec,

I applied your suggestion and run maple. It run for 40 min and vitual problem exited, son I had to stop running :((((

thanks for your helps, I hope there will be a solution :)

AA

## sorry,  sometimes being...

sorry,  sometimes being fool is the good way of learning  :)

why  f =1 and c = 0,

I try to run maple for the last case

greets

AA

## Dear Writers, thank you all...

Dear Writers,

thank you all for the suggestions but I am not a mathematician :(   therefore It seems difficult for me to follow you in detail.

Dear Alec, if possible , could you  please send me maple file so that I can wait till the end of solution.

this equation comes from a physical modelling :(

thank you

AA

## Dear Robert Isreal,   first...

Dear Robert Isreal,

first of all I appreciate that you spent time for me :) thank you.  This is a really a big problem for me that I was not able to solve :((((  I hope Maple 13 can solve this  :))problem :))))

However I require the complete solution especially for  e value :)

Thanks a lot

AA

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