Why The Interval of f(x) is the same in Both One and Two Side Limits?












0












$begingroup$


My Question might be wired For some But It Will help me to get the idea of One Side Limits.



My Book



Recall The Definition of One Side Limits :




  • Right Hand Limit


if for every number ϵ>0 there is a number δ>0 such that



$$c<x<c+δ quadlongrightarrowquad lvert f(x)- llvert<ϵ $$




  • Lift hand Limit


if for every number ϵ>0 there is a number δ>0 such that
$$c-δ<x<c quadlongrightarrowquad lvert f(x)- llvert<ϵ $$



My Question



It Might Be weird to me That putting an Interval



$$lvert f(x)- llvert<ϵ$$



in Either One of the definitions.



Consider Right hand limit, I'm assume that we need an interval such
$$l<f(x)<l+ϵ quad$$



enter image description here



Because It's Impossible to get any value at $$c<x$$



and The same Thing for Left hand Side , we might put $$l-ϵ<f(x)<l quad$$ instead of $$l-ϵ<f(x)<l+ϵ quad$$ Since it's also impassible for $$c>x$$



enter image description here



What is the point of Use $$lvert f(x)- llvert<ϵ $$ instead of what Just I Wrote of intervals For set the interval of Epsilon?



Thanks in advance










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    What if $f$ is decreasing?
    $endgroup$
    – Hans Lundmark
    Jan 5 at 11:01










  • $begingroup$
    Using $x>c$ does not necessarily imply $f(x) >l$. The right/left refers to values of $x$ with respect to $c$ and not to values of $f(x) $.
    $endgroup$
    – Paramanand Singh
    Jan 5 at 12:52










  • $begingroup$
    @ParamanandSingh- meaning there are cases we will have $$x>c$$ for $$|f(x)-l|<ϵ$$?! Could you give me an example for limit in this case where $$x>c$$ pointing to $$f(x)<l$$
    $endgroup$
    – Ammar Bamhdi
    Jan 6 at 0:36


















0












$begingroup$


My Question might be wired For some But It Will help me to get the idea of One Side Limits.



My Book



Recall The Definition of One Side Limits :




  • Right Hand Limit


if for every number ϵ>0 there is a number δ>0 such that



$$c<x<c+δ quadlongrightarrowquad lvert f(x)- llvert<ϵ $$




  • Lift hand Limit


if for every number ϵ>0 there is a number δ>0 such that
$$c-δ<x<c quadlongrightarrowquad lvert f(x)- llvert<ϵ $$



My Question



It Might Be weird to me That putting an Interval



$$lvert f(x)- llvert<ϵ$$



in Either One of the definitions.



Consider Right hand limit, I'm assume that we need an interval such
$$l<f(x)<l+ϵ quad$$



enter image description here



Because It's Impossible to get any value at $$c<x$$



and The same Thing for Left hand Side , we might put $$l-ϵ<f(x)<l quad$$ instead of $$l-ϵ<f(x)<l+ϵ quad$$ Since it's also impassible for $$c>x$$



enter image description here



What is the point of Use $$lvert f(x)- llvert<ϵ $$ instead of what Just I Wrote of intervals For set the interval of Epsilon?



Thanks in advance










share|cite|improve this question









$endgroup$








  • 1




    $begingroup$
    What if $f$ is decreasing?
    $endgroup$
    – Hans Lundmark
    Jan 5 at 11:01










  • $begingroup$
    Using $x>c$ does not necessarily imply $f(x) >l$. The right/left refers to values of $x$ with respect to $c$ and not to values of $f(x) $.
    $endgroup$
    – Paramanand Singh
    Jan 5 at 12:52










  • $begingroup$
    @ParamanandSingh- meaning there are cases we will have $$x>c$$ for $$|f(x)-l|<ϵ$$?! Could you give me an example for limit in this case where $$x>c$$ pointing to $$f(x)<l$$
    $endgroup$
    – Ammar Bamhdi
    Jan 6 at 0:36
















0












0








0





$begingroup$


My Question might be wired For some But It Will help me to get the idea of One Side Limits.



My Book



Recall The Definition of One Side Limits :




  • Right Hand Limit


if for every number ϵ>0 there is a number δ>0 such that



$$c<x<c+δ quadlongrightarrowquad lvert f(x)- llvert<ϵ $$




  • Lift hand Limit


if for every number ϵ>0 there is a number δ>0 such that
$$c-δ<x<c quadlongrightarrowquad lvert f(x)- llvert<ϵ $$



My Question



It Might Be weird to me That putting an Interval



$$lvert f(x)- llvert<ϵ$$



in Either One of the definitions.



Consider Right hand limit, I'm assume that we need an interval such
$$l<f(x)<l+ϵ quad$$



enter image description here



Because It's Impossible to get any value at $$c<x$$



and The same Thing for Left hand Side , we might put $$l-ϵ<f(x)<l quad$$ instead of $$l-ϵ<f(x)<l+ϵ quad$$ Since it's also impassible for $$c>x$$



enter image description here



What is the point of Use $$lvert f(x)- llvert<ϵ $$ instead of what Just I Wrote of intervals For set the interval of Epsilon?



Thanks in advance










share|cite|improve this question









$endgroup$




My Question might be wired For some But It Will help me to get the idea of One Side Limits.



My Book



Recall The Definition of One Side Limits :




  • Right Hand Limit


if for every number ϵ>0 there is a number δ>0 such that



$$c<x<c+δ quadlongrightarrowquad lvert f(x)- llvert<ϵ $$




  • Lift hand Limit


if for every number ϵ>0 there is a number δ>0 such that
$$c-δ<x<c quadlongrightarrowquad lvert f(x)- llvert<ϵ $$



My Question



It Might Be weird to me That putting an Interval



$$lvert f(x)- llvert<ϵ$$



in Either One of the definitions.



Consider Right hand limit, I'm assume that we need an interval such
$$l<f(x)<l+ϵ quad$$



enter image description here



Because It's Impossible to get any value at $$c<x$$



and The same Thing for Left hand Side , we might put $$l-ϵ<f(x)<l quad$$ instead of $$l-ϵ<f(x)<l+ϵ quad$$ Since it's also impassible for $$c>x$$



enter image description here



What is the point of Use $$lvert f(x)- llvert<ϵ $$ instead of what Just I Wrote of intervals For set the interval of Epsilon?



Thanks in advance







calculus limits






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Jan 5 at 8:11









Ammar BamhdiAmmar Bamhdi

325




325








  • 1




    $begingroup$
    What if $f$ is decreasing?
    $endgroup$
    – Hans Lundmark
    Jan 5 at 11:01










  • $begingroup$
    Using $x>c$ does not necessarily imply $f(x) >l$. The right/left refers to values of $x$ with respect to $c$ and not to values of $f(x) $.
    $endgroup$
    – Paramanand Singh
    Jan 5 at 12:52










  • $begingroup$
    @ParamanandSingh- meaning there are cases we will have $$x>c$$ for $$|f(x)-l|<ϵ$$?! Could you give me an example for limit in this case where $$x>c$$ pointing to $$f(x)<l$$
    $endgroup$
    – Ammar Bamhdi
    Jan 6 at 0:36
















  • 1




    $begingroup$
    What if $f$ is decreasing?
    $endgroup$
    – Hans Lundmark
    Jan 5 at 11:01










  • $begingroup$
    Using $x>c$ does not necessarily imply $f(x) >l$. The right/left refers to values of $x$ with respect to $c$ and not to values of $f(x) $.
    $endgroup$
    – Paramanand Singh
    Jan 5 at 12:52










  • $begingroup$
    @ParamanandSingh- meaning there are cases we will have $$x>c$$ for $$|f(x)-l|<ϵ$$?! Could you give me an example for limit in this case where $$x>c$$ pointing to $$f(x)<l$$
    $endgroup$
    – Ammar Bamhdi
    Jan 6 at 0:36










1




1




$begingroup$
What if $f$ is decreasing?
$endgroup$
– Hans Lundmark
Jan 5 at 11:01




$begingroup$
What if $f$ is decreasing?
$endgroup$
– Hans Lundmark
Jan 5 at 11:01












$begingroup$
Using $x>c$ does not necessarily imply $f(x) >l$. The right/left refers to values of $x$ with respect to $c$ and not to values of $f(x) $.
$endgroup$
– Paramanand Singh
Jan 5 at 12:52




$begingroup$
Using $x>c$ does not necessarily imply $f(x) >l$. The right/left refers to values of $x$ with respect to $c$ and not to values of $f(x) $.
$endgroup$
– Paramanand Singh
Jan 5 at 12:52












$begingroup$
@ParamanandSingh- meaning there are cases we will have $$x>c$$ for $$|f(x)-l|<ϵ$$?! Could you give me an example for limit in this case where $$x>c$$ pointing to $$f(x)<l$$
$endgroup$
– Ammar Bamhdi
Jan 6 at 0:36






$begingroup$
@ParamanandSingh- meaning there are cases we will have $$x>c$$ for $$|f(x)-l|<ϵ$$?! Could you give me an example for limit in this case where $$x>c$$ pointing to $$f(x)<l$$
$endgroup$
– Ammar Bamhdi
Jan 6 at 0:36












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%2f3062509%2fwhy-the-interval-of-fx-is-the-same-in-both-one-and-two-side-limits%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%2f3062509%2fwhy-the-interval-of-fx-is-the-same-in-both-one-and-two-side-limits%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

Bressuire

Cabo Verde

Gyllenstierna