Can someone help me solve this limit?
$begingroup$
Can someone help me solve this limit? Thank you in advance.
$$lim_{xto 0} bigg( frac{1+tan{x}}{1+sin{x}} bigg)^{frac{1}{sin{x}}}$$
If possible without L'Hospital, the exercise gives more points if we solve it without it.
real-analysis calculus limits
New contributor
$endgroup$
add a comment |
$begingroup$
Can someone help me solve this limit? Thank you in advance.
$$lim_{xto 0} bigg( frac{1+tan{x}}{1+sin{x}} bigg)^{frac{1}{sin{x}}}$$
If possible without L'Hospital, the exercise gives more points if we solve it without it.
real-analysis calculus limits
New contributor
$endgroup$
1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
9 hours ago
$begingroup$
Hint: $sin x$ and $tan x$ can be replaced by $x$, to the first order. The limit is that of $(1+o(x))^{1/x}$.
$endgroup$
– Yves Daoust
9 hours ago
$begingroup$
I have forgot to add the last part that if it is possible to not use L'Hospital , because if we use it in places where they think we could have used something else , they penalise us
$endgroup$
– user644728
8 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
8 hours ago
add a comment |
$begingroup$
Can someone help me solve this limit? Thank you in advance.
$$lim_{xto 0} bigg( frac{1+tan{x}}{1+sin{x}} bigg)^{frac{1}{sin{x}}}$$
If possible without L'Hospital, the exercise gives more points if we solve it without it.
real-analysis calculus limits
New contributor
$endgroup$
Can someone help me solve this limit? Thank you in advance.
$$lim_{xto 0} bigg( frac{1+tan{x}}{1+sin{x}} bigg)^{frac{1}{sin{x}}}$$
If possible without L'Hospital, the exercise gives more points if we solve it without it.
real-analysis calculus limits
real-analysis calculus limits
New contributor
New contributor
edited 8 hours ago
Lemniscate
402211
402211
New contributor
asked 9 hours ago
user644728user644728
325
325
New contributor
New contributor
1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
9 hours ago
$begingroup$
Hint: $sin x$ and $tan x$ can be replaced by $x$, to the first order. The limit is that of $(1+o(x))^{1/x}$.
$endgroup$
– Yves Daoust
9 hours ago
$begingroup$
I have forgot to add the last part that if it is possible to not use L'Hospital , because if we use it in places where they think we could have used something else , they penalise us
$endgroup$
– user644728
8 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
8 hours ago
add a comment |
1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
9 hours ago
$begingroup$
Hint: $sin x$ and $tan x$ can be replaced by $x$, to the first order. The limit is that of $(1+o(x))^{1/x}$.
$endgroup$
– Yves Daoust
9 hours ago
$begingroup$
I have forgot to add the last part that if it is possible to not use L'Hospital , because if we use it in places where they think we could have used something else , they penalise us
$endgroup$
– user644728
8 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
8 hours ago
1
1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
9 hours ago
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
9 hours ago
$begingroup$
Hint: $sin x$ and $tan x$ can be replaced by $x$, to the first order. The limit is that of $(1+o(x))^{1/x}$.
$endgroup$
– Yves Daoust
9 hours ago
$begingroup$
Hint: $sin x$ and $tan x$ can be replaced by $x$, to the first order. The limit is that of $(1+o(x))^{1/x}$.
$endgroup$
– Yves Daoust
9 hours ago
$begingroup$
I have forgot to add the last part that if it is possible to not use L'Hospital , because if we use it in places where they think we could have used something else , they penalise us
$endgroup$
– user644728
8 hours ago
$begingroup$
I have forgot to add the last part that if it is possible to not use L'Hospital , because if we use it in places where they think we could have used something else , they penalise us
$endgroup$
– user644728
8 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
8 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
8 hours ago
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
$hspace{5mm} lim_{xto 0}left(frac{1+tan(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1+tan(x)}{1+sin(x)}-1right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{tan(x)-sin(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left[left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{frac{1+sin(x)}{tan(x)-sin(x)}}right]^{tfrac{1}{sin(x)} cdot frac{tan(x)-sin(x)}{1+sin(x)}}$
$=mathrm{exp} big( {lim_{xto 0}tfrac{1}{sin(x)} frac{tan(x)-sin(x)}{1+sin(x)}} big)$
$=mathrm{exp} big( {lim_{xto 0}frac{1-cos(x)}{cos(x)(1+sin(x))}} big)$
$=mathrm{exp} big( {frac{1-1}{1(1+0)}} big)$
$=e^0$
$=1$
$endgroup$
add a comment |
$begingroup$
The searched limit is the ratio
$$frac{lim_{xto0}(1+tan x)^{1/sin x}}{lim_{xto0}(1+sin x)^{1/sin x}}=frac{lim_{xto0}((1+tan x)^{1/tan x})^{1/cos x}}{lim_{xto0}(1+sin x)^{1/sin x}}.$$
As $tan x$ and $sin x$ tend to zero continuously with $x$, $$frac{e^1}e.$$
$endgroup$
add a comment |
$begingroup$
Let
$$L=lim_{xto 0} (frac{1+tan{(x)}}{1+sin{(x)}})^{frac{1}{sin{(x)}}}$$
$$ln{L}=lim_{xto 0} frac{1}{sin{(x)}}ln{(frac{1+tan{(x)}}{1+sin{(x)}})}$$
$$ln{L}=lim_{xto 0} frac{ln{(1+tan{(x)})}-ln{(1+sin{(x)})})}{sin{(x)}}$$
$$ln{L}=lim_{xto 0} frac{frac{sec^2{(x)}}{1+tan{(x)}}-frac{cos{(x)}}{1+sin{(x)}}}{cos{(x)}}$$
$$ln{L}=lim_{xto 0} frac{1}{cos^3{(x)}(1+tan{(x)})}-frac{1}{1+sin{(x)}}$$
$$ln{L}= 1-1=0$$
$$therefore L=e^0=1$$
$endgroup$
add a comment |
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
});
}
});
user644728 is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3116681%2fcan-someone-help-me-solve-this-limit%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
$hspace{5mm} lim_{xto 0}left(frac{1+tan(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1+tan(x)}{1+sin(x)}-1right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{tan(x)-sin(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left[left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{frac{1+sin(x)}{tan(x)-sin(x)}}right]^{tfrac{1}{sin(x)} cdot frac{tan(x)-sin(x)}{1+sin(x)}}$
$=mathrm{exp} big( {lim_{xto 0}tfrac{1}{sin(x)} frac{tan(x)-sin(x)}{1+sin(x)}} big)$
$=mathrm{exp} big( {lim_{xto 0}frac{1-cos(x)}{cos(x)(1+sin(x))}} big)$
$=mathrm{exp} big( {frac{1-1}{1(1+0)}} big)$
$=e^0$
$=1$
$endgroup$
add a comment |
$begingroup$
$hspace{5mm} lim_{xto 0}left(frac{1+tan(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1+tan(x)}{1+sin(x)}-1right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{tan(x)-sin(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left[left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{frac{1+sin(x)}{tan(x)-sin(x)}}right]^{tfrac{1}{sin(x)} cdot frac{tan(x)-sin(x)}{1+sin(x)}}$
$=mathrm{exp} big( {lim_{xto 0}tfrac{1}{sin(x)} frac{tan(x)-sin(x)}{1+sin(x)}} big)$
$=mathrm{exp} big( {lim_{xto 0}frac{1-cos(x)}{cos(x)(1+sin(x))}} big)$
$=mathrm{exp} big( {frac{1-1}{1(1+0)}} big)$
$=e^0$
$=1$
$endgroup$
add a comment |
$begingroup$
$hspace{5mm} lim_{xto 0}left(frac{1+tan(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1+tan(x)}{1+sin(x)}-1right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{tan(x)-sin(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left[left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{frac{1+sin(x)}{tan(x)-sin(x)}}right]^{tfrac{1}{sin(x)} cdot frac{tan(x)-sin(x)}{1+sin(x)}}$
$=mathrm{exp} big( {lim_{xto 0}tfrac{1}{sin(x)} frac{tan(x)-sin(x)}{1+sin(x)}} big)$
$=mathrm{exp} big( {lim_{xto 0}frac{1-cos(x)}{cos(x)(1+sin(x))}} big)$
$=mathrm{exp} big( {frac{1-1}{1(1+0)}} big)$
$=e^0$
$=1$
$endgroup$
$hspace{5mm} lim_{xto 0}left(frac{1+tan(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1+tan(x)}{1+sin(x)}-1right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{tan(x)-sin(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left[left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{frac{1+sin(x)}{tan(x)-sin(x)}}right]^{tfrac{1}{sin(x)} cdot frac{tan(x)-sin(x)}{1+sin(x)}}$
$=mathrm{exp} big( {lim_{xto 0}tfrac{1}{sin(x)} frac{tan(x)-sin(x)}{1+sin(x)}} big)$
$=mathrm{exp} big( {lim_{xto 0}frac{1-cos(x)}{cos(x)(1+sin(x))}} big)$
$=mathrm{exp} big( {frac{1-1}{1(1+0)}} big)$
$=e^0$
$=1$
edited 8 hours ago
Lemniscate
402211
402211
answered 8 hours ago
user326159user326159
1,2621722
1,2621722
add a comment |
add a comment |
$begingroup$
The searched limit is the ratio
$$frac{lim_{xto0}(1+tan x)^{1/sin x}}{lim_{xto0}(1+sin x)^{1/sin x}}=frac{lim_{xto0}((1+tan x)^{1/tan x})^{1/cos x}}{lim_{xto0}(1+sin x)^{1/sin x}}.$$
As $tan x$ and $sin x$ tend to zero continuously with $x$, $$frac{e^1}e.$$
$endgroup$
add a comment |
$begingroup$
The searched limit is the ratio
$$frac{lim_{xto0}(1+tan x)^{1/sin x}}{lim_{xto0}(1+sin x)^{1/sin x}}=frac{lim_{xto0}((1+tan x)^{1/tan x})^{1/cos x}}{lim_{xto0}(1+sin x)^{1/sin x}}.$$
As $tan x$ and $sin x$ tend to zero continuously with $x$, $$frac{e^1}e.$$
$endgroup$
add a comment |
$begingroup$
The searched limit is the ratio
$$frac{lim_{xto0}(1+tan x)^{1/sin x}}{lim_{xto0}(1+sin x)^{1/sin x}}=frac{lim_{xto0}((1+tan x)^{1/tan x})^{1/cos x}}{lim_{xto0}(1+sin x)^{1/sin x}}.$$
As $tan x$ and $sin x$ tend to zero continuously with $x$, $$frac{e^1}e.$$
$endgroup$
The searched limit is the ratio
$$frac{lim_{xto0}(1+tan x)^{1/sin x}}{lim_{xto0}(1+sin x)^{1/sin x}}=frac{lim_{xto0}((1+tan x)^{1/tan x})^{1/cos x}}{lim_{xto0}(1+sin x)^{1/sin x}}.$$
As $tan x$ and $sin x$ tend to zero continuously with $x$, $$frac{e^1}e.$$
edited 8 hours ago
answered 8 hours ago
Yves DaoustYves Daoust
128k675227
128k675227
add a comment |
add a comment |
$begingroup$
Let
$$L=lim_{xto 0} (frac{1+tan{(x)}}{1+sin{(x)}})^{frac{1}{sin{(x)}}}$$
$$ln{L}=lim_{xto 0} frac{1}{sin{(x)}}ln{(frac{1+tan{(x)}}{1+sin{(x)}})}$$
$$ln{L}=lim_{xto 0} frac{ln{(1+tan{(x)})}-ln{(1+sin{(x)})})}{sin{(x)}}$$
$$ln{L}=lim_{xto 0} frac{frac{sec^2{(x)}}{1+tan{(x)}}-frac{cos{(x)}}{1+sin{(x)}}}{cos{(x)}}$$
$$ln{L}=lim_{xto 0} frac{1}{cos^3{(x)}(1+tan{(x)})}-frac{1}{1+sin{(x)}}$$
$$ln{L}= 1-1=0$$
$$therefore L=e^0=1$$
$endgroup$
add a comment |
$begingroup$
Let
$$L=lim_{xto 0} (frac{1+tan{(x)}}{1+sin{(x)}})^{frac{1}{sin{(x)}}}$$
$$ln{L}=lim_{xto 0} frac{1}{sin{(x)}}ln{(frac{1+tan{(x)}}{1+sin{(x)}})}$$
$$ln{L}=lim_{xto 0} frac{ln{(1+tan{(x)})}-ln{(1+sin{(x)})})}{sin{(x)}}$$
$$ln{L}=lim_{xto 0} frac{frac{sec^2{(x)}}{1+tan{(x)}}-frac{cos{(x)}}{1+sin{(x)}}}{cos{(x)}}$$
$$ln{L}=lim_{xto 0} frac{1}{cos^3{(x)}(1+tan{(x)})}-frac{1}{1+sin{(x)}}$$
$$ln{L}= 1-1=0$$
$$therefore L=e^0=1$$
$endgroup$
add a comment |
$begingroup$
Let
$$L=lim_{xto 0} (frac{1+tan{(x)}}{1+sin{(x)}})^{frac{1}{sin{(x)}}}$$
$$ln{L}=lim_{xto 0} frac{1}{sin{(x)}}ln{(frac{1+tan{(x)}}{1+sin{(x)}})}$$
$$ln{L}=lim_{xto 0} frac{ln{(1+tan{(x)})}-ln{(1+sin{(x)})})}{sin{(x)}}$$
$$ln{L}=lim_{xto 0} frac{frac{sec^2{(x)}}{1+tan{(x)}}-frac{cos{(x)}}{1+sin{(x)}}}{cos{(x)}}$$
$$ln{L}=lim_{xto 0} frac{1}{cos^3{(x)}(1+tan{(x)})}-frac{1}{1+sin{(x)}}$$
$$ln{L}= 1-1=0$$
$$therefore L=e^0=1$$
$endgroup$
Let
$$L=lim_{xto 0} (frac{1+tan{(x)}}{1+sin{(x)}})^{frac{1}{sin{(x)}}}$$
$$ln{L}=lim_{xto 0} frac{1}{sin{(x)}}ln{(frac{1+tan{(x)}}{1+sin{(x)}})}$$
$$ln{L}=lim_{xto 0} frac{ln{(1+tan{(x)})}-ln{(1+sin{(x)})})}{sin{(x)}}$$
$$ln{L}=lim_{xto 0} frac{frac{sec^2{(x)}}{1+tan{(x)}}-frac{cos{(x)}}{1+sin{(x)}}}{cos{(x)}}$$
$$ln{L}=lim_{xto 0} frac{1}{cos^3{(x)}(1+tan{(x)})}-frac{1}{1+sin{(x)}}$$
$$ln{L}= 1-1=0$$
$$therefore L=e^0=1$$
answered 8 hours ago
Peter ForemanPeter Foreman
2,13613
2,13613
add a comment |
add a comment |
user644728 is a new contributor. Be nice, and check out our Code of Conduct.
user644728 is a new contributor. Be nice, and check out our Code of Conduct.
user644728 is a new contributor. Be nice, and check out our Code of Conduct.
user644728 is a new contributor. Be nice, and check out our Code of Conduct.
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.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3116681%2fcan-someone-help-me-solve-this-limit%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
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
1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
9 hours ago
$begingroup$
Hint: $sin x$ and $tan x$ can be replaced by $x$, to the first order. The limit is that of $(1+o(x))^{1/x}$.
$endgroup$
– Yves Daoust
9 hours ago
$begingroup$
I have forgot to add the last part that if it is possible to not use L'Hospital , because if we use it in places where they think we could have used something else , they penalise us
$endgroup$
– user644728
8 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
8 hours ago