On the existence and uniqueness of solutions of non-linear differential equation system












0












$begingroup$


Are there theorems that could be applied to show the existence/uniqueness of solution of such system :



$$
(S) left { begin{aligned}
p''&= f_1(b) \
q'' &= f_2(x,p,q,b)\
q~~ &= f_3(x,p,b)
end{aligned}
right.
$$



where $f_1$, $f_2$ and $f_3$ are non linear functions ? and $p$, $b$ and $q$ are real and positive functions defined on a compact $[a,b] subset mathbb{R+}$ ?










share|cite|improve this question











$endgroup$












  • $begingroup$
    Is the last line of $(S)$ supposed to be $q=...$?
    $endgroup$
    – Not Mike
    Dec 4 '18 at 17:11










  • $begingroup$
    Yes why ? it characterizes how q is a function of the other unknowns $p$ and $b$.
    $endgroup$
    – AlexC75
    Dec 4 '18 at 17:12








  • 1




    $begingroup$
    If or where the last equation can be solved for $b$ this is an index-1 DAE in semi-explicit form. The general theory of differential-algebraic equations applies, which gives here apart from said solvability no further restrictions.
    $endgroup$
    – LutzL
    Dec 4 '18 at 17:21
















0












$begingroup$


Are there theorems that could be applied to show the existence/uniqueness of solution of such system :



$$
(S) left { begin{aligned}
p''&= f_1(b) \
q'' &= f_2(x,p,q,b)\
q~~ &= f_3(x,p,b)
end{aligned}
right.
$$



where $f_1$, $f_2$ and $f_3$ are non linear functions ? and $p$, $b$ and $q$ are real and positive functions defined on a compact $[a,b] subset mathbb{R+}$ ?










share|cite|improve this question











$endgroup$












  • $begingroup$
    Is the last line of $(S)$ supposed to be $q=...$?
    $endgroup$
    – Not Mike
    Dec 4 '18 at 17:11










  • $begingroup$
    Yes why ? it characterizes how q is a function of the other unknowns $p$ and $b$.
    $endgroup$
    – AlexC75
    Dec 4 '18 at 17:12








  • 1




    $begingroup$
    If or where the last equation can be solved for $b$ this is an index-1 DAE in semi-explicit form. The general theory of differential-algebraic equations applies, which gives here apart from said solvability no further restrictions.
    $endgroup$
    – LutzL
    Dec 4 '18 at 17:21














0












0








0





$begingroup$


Are there theorems that could be applied to show the existence/uniqueness of solution of such system :



$$
(S) left { begin{aligned}
p''&= f_1(b) \
q'' &= f_2(x,p,q,b)\
q~~ &= f_3(x,p,b)
end{aligned}
right.
$$



where $f_1$, $f_2$ and $f_3$ are non linear functions ? and $p$, $b$ and $q$ are real and positive functions defined on a compact $[a,b] subset mathbb{R+}$ ?










share|cite|improve this question











$endgroup$




Are there theorems that could be applied to show the existence/uniqueness of solution of such system :



$$
(S) left { begin{aligned}
p''&= f_1(b) \
q'' &= f_2(x,p,q,b)\
q~~ &= f_3(x,p,b)
end{aligned}
right.
$$



where $f_1$, $f_2$ and $f_3$ are non linear functions ? and $p$, $b$ and $q$ are real and positive functions defined on a compact $[a,b] subset mathbb{R+}$ ?







differential-equations nonlinear-system






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 4 '18 at 17:16









LutzL

56.7k42054




56.7k42054










asked Dec 4 '18 at 17:00









AlexC75AlexC75

216




216












  • $begingroup$
    Is the last line of $(S)$ supposed to be $q=...$?
    $endgroup$
    – Not Mike
    Dec 4 '18 at 17:11










  • $begingroup$
    Yes why ? it characterizes how q is a function of the other unknowns $p$ and $b$.
    $endgroup$
    – AlexC75
    Dec 4 '18 at 17:12








  • 1




    $begingroup$
    If or where the last equation can be solved for $b$ this is an index-1 DAE in semi-explicit form. The general theory of differential-algebraic equations applies, which gives here apart from said solvability no further restrictions.
    $endgroup$
    – LutzL
    Dec 4 '18 at 17:21


















  • $begingroup$
    Is the last line of $(S)$ supposed to be $q=...$?
    $endgroup$
    – Not Mike
    Dec 4 '18 at 17:11










  • $begingroup$
    Yes why ? it characterizes how q is a function of the other unknowns $p$ and $b$.
    $endgroup$
    – AlexC75
    Dec 4 '18 at 17:12








  • 1




    $begingroup$
    If or where the last equation can be solved for $b$ this is an index-1 DAE in semi-explicit form. The general theory of differential-algebraic equations applies, which gives here apart from said solvability no further restrictions.
    $endgroup$
    – LutzL
    Dec 4 '18 at 17:21
















$begingroup$
Is the last line of $(S)$ supposed to be $q=...$?
$endgroup$
– Not Mike
Dec 4 '18 at 17:11




$begingroup$
Is the last line of $(S)$ supposed to be $q=...$?
$endgroup$
– Not Mike
Dec 4 '18 at 17:11












$begingroup$
Yes why ? it characterizes how q is a function of the other unknowns $p$ and $b$.
$endgroup$
– AlexC75
Dec 4 '18 at 17:12






$begingroup$
Yes why ? it characterizes how q is a function of the other unknowns $p$ and $b$.
$endgroup$
– AlexC75
Dec 4 '18 at 17:12






1




1




$begingroup$
If or where the last equation can be solved for $b$ this is an index-1 DAE in semi-explicit form. The general theory of differential-algebraic equations applies, which gives here apart from said solvability no further restrictions.
$endgroup$
– LutzL
Dec 4 '18 at 17:21




$begingroup$
If or where the last equation can be solved for $b$ this is an index-1 DAE in semi-explicit form. The general theory of differential-algebraic equations applies, which gives here apart from said solvability no further restrictions.
$endgroup$
– LutzL
Dec 4 '18 at 17:21










0






active

oldest

votes











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3025829%2fon-the-existence-and-uniqueness-of-solutions-of-non-linear-differential-equation%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3025829%2fon-the-existence-and-uniqueness-of-solutions-of-non-linear-differential-equation%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Wiesbaden

Marschland

Dieringhausen