Message Boards Message Boards

0
|
2559 Views
|
2 Replies
|
1 Total Likes
View groups...
Share
Share this post:

[?] Solve and Plot numerically this differential equation?

Posted 7 years ago

Consider the following code:

e1 = 0.001;
e^0.4 = {{2.37/de^0.06} - 1.6}/10 {1 - Log[de]/13.8}^0.7

the initial value is e1=0.001 for t0=1 and the time period is between {t,1,18000}

POSTED BY: dimitriss mal
2 Replies
Posted 7 years ago

Thank you very much for your aswer!!!it works perfect!!!!

POSTED BY: dimitriss mal

Your equation is implicit in the derivative. We can work around the problem by taking the derivative of the equation, which makes it explicit in the second derivative. If I don't misunderstand your syntax, here is an attempt:

eq = e[t]^(4/10) == (((237/100)/e'[t]^ (6/100)) - 
     16/10)/(10 (1 - Log[e'[t]]/(138/10))^(7/100))
deq = Simplify@D[eq, t]
de1 = e'[1] /. 
   Solve[eq /. {t -> 1} /. e[1] -> 1/1000, e'[1], Reals][[1]] // N
sol = NDSolveValue[{deq, e[1] == 1/1000, e'[1] == de1}, 
  e, {t, 1, 18000}]
Plot[sol[t], {t, 1, 18000}]
POSTED BY: Gianluca Gorni
Reply to this discussion
Community posts can be styled and formatted using the Markdown syntax.
Reply Preview
Attachments
Remove
or Discard

Group Abstract Group Abstract