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
3 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
3 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
3 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
2 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 3 hours ago
Lemniscate
402211
402211
New contributor
asked 3 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
3 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
3 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
3 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
2 hours ago
add a comment |
1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
3 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
3 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
3 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
2 hours ago
1
1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
3 hours ago
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
3 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
3 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
3 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
3 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
3 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
2 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
2 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 |
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3 Answers
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3 Answers
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$begingroup$
$hspace{5mm} lim_{xto 0}left(frac{1+tan(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1+tan(x)}{1+sin(x)}-1right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{tan(x)-sin(x)}{1+sin(x)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{tfrac{1}{sin(x)}}$
$=lim_{xto 0}left[left(1+frac{1}{big(frac{1+sin(x)}{tan(x)-sin(x)}big)}right)^{frac{1+sin(x)}{tan(x)-sin(x)}}right]^{tfrac{1}{sin(x)} cdot frac{tan(x)-sin(x)}{1+sin(x)}}$
$=mathrm{exp} big( {lim_{xto 0}tfrac{1}{sin(x)} frac{tan(x)-sin(x)}{1+sin(x)}} big)$
$=mathrm{exp} big( {lim_{xto 0}frac{1-cos(x)}{cos(x)(1+sin(x))}} big)$
$=mathrm{exp} big( {frac{1-1}{1(1+0)}} big)$
$=e^0$
$=1$
$endgroup$
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 3 hours ago
Lemniscate
402211
402211
answered 3 hours ago
user326159user326159
1,2521722
1,2521722
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 2 hours ago
answered 3 hours ago
Yves DaoustYves Daoust
128k674227
128k674227
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 3 hours ago
Peter ForemanPeter Foreman
2,13613
2,13613
add a comment |
add a comment |
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1
$begingroup$
Looks like a case for the rule of L'Hospital. Have you tried that?
$endgroup$
– Cornman
3 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
3 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
3 hours ago
$begingroup$
"Can someone help me solve this limit?" And how is that supposed to help you learn?
$endgroup$
– John Coleman
2 hours ago