Evaluate $ lim_xrightarrow 0left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right) $ The 2019 Stack Overflow Developer Survey Results Are InCalculate: $lim_n rightarrowinftyleft(frac3^-nsin(3^(1-n))tan(3^1-2n) right)$computing $lim_x to 0 fracsin2x+arctan3x+3x^2lnleft(1+3x+sin^2xright)+xcdot e^x$Solve limit without use L'Hopital: $lim _xto 0left(fracsinleft(2xright)-2sinleft(xright)xcdot :arctg^2xright)$$lim_xto 1/2 left(fractan(pi x)2x-1+frac2pi(2x-1)^2right)$ using L' HopitalShow that $lim_n rightarrow inftyleft(n^2 - frac1sin^2(frac1n) right)=-frac13$Find $lim_xrightarrow fracpi4left(fracsin xcos xright)^left(fracsin 2xcos 2xright)$How can I calculate the following limit? $beginequation* lim_x rightarrow 0 fractan(x) - sin(x)x^3 endequation*,$No L' Hospital $ lim_x rightarrow 0 left (1+frac 1 arctan x right)^sin x$ and $ lim_x rightarrow 0 frac tan ^7 x ln (7x+1) $Calculating $lim_x rightarrow 0 fractan x - sin xx^3$.Evaluate: $lim_xto0left (frac4^tan(x)+ cos(x)2right)^cot(x)$
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Evaluate $ lim_xrightarrow 0left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right) $
The 2019 Stack Overflow Developer Survey Results Are InCalculate: $lim_n rightarrowinftyleft(frac3^-nsin(3^(1-n))tan(3^1-2n) right)$computing $lim_x to 0 fracsin2x+arctan3x+3x^2lnleft(1+3x+sin^2xright)+xcdot e^x$Solve limit without use L'Hopital: $lim _xto 0left(fracsinleft(2xright)-2sinleft(xright)xcdot :arctg^2xright)$$lim_xto 1/2 left(fractan(pi x)2x-1+frac2pi(2x-1)^2right)$ using L' HopitalShow that $lim_n rightarrow inftyleft(n^2 - frac1sin^2(frac1n) right)=-frac13$Find $lim_xrightarrow fracpi4left(fracsin xcos xright)^left(fracsin 2xcos 2xright)$How can I calculate the following limit? $beginequation* lim_x rightarrow 0 fractan(x) - sin(x)x^3 endequation*,$No L' Hospital $ lim_x rightarrow 0 left (1+frac 1 arctan x right)^sin x$ and $ lim_x rightarrow 0 frac tan ^7 x ln (7x+1) $Calculating $lim_x rightarrow 0 fractan x - sin xx^3$.Evaluate: $lim_xto0left (frac4^tan(x)+ cos(x)2right)^cot(x)$
$begingroup$
Calculate the limit
$$
lim_xrightarrow 0left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
$$
My try was to use the Taylor expansion of the denominator and numerator but it wasn't beauty approach.
real-analysis limits
$endgroup$
add a comment |
$begingroup$
Calculate the limit
$$
lim_xrightarrow 0left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
$$
My try was to use the Taylor expansion of the denominator and numerator but it wasn't beauty approach.
real-analysis limits
$endgroup$
add a comment |
$begingroup$
Calculate the limit
$$
lim_xrightarrow 0left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
$$
My try was to use the Taylor expansion of the denominator and numerator but it wasn't beauty approach.
real-analysis limits
$endgroup$
Calculate the limit
$$
lim_xrightarrow 0left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
$$
My try was to use the Taylor expansion of the denominator and numerator but it wasn't beauty approach.
real-analysis limits
real-analysis limits
edited Mar 23 at 16:44
Jneven
953322
953322
asked Mar 23 at 16:01
avan1235avan1235
3598
3598
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
Let $u=xsin x$
$$lim_uto 0left(dfrac1utan u-dfrac1u^2right)=lim_uto 0dfracu-tan uu^2tan u$$
Can you proceed?
$endgroup$
1
$begingroup$
I've corrected some errors, but the conversion back to $x$-space is unnecessary.
$endgroup$
– J.G.
Mar 23 at 16:13
$begingroup$
I'll remove that then @J.G.Thanks. Cheers :))
$endgroup$
– Paras Khosla
Mar 23 at 16:13
$begingroup$
Thanks, whats the official arguemnt to change $xsin(x)$ to $u$?
$endgroup$
– avan1235
Mar 23 at 16:14
2
$begingroup$
@avan1235 $lim_xto af(g(x))=lim_utolim_xto ag(x)f(u)$ provided $lim_xto ag(x)$ exists.
$endgroup$
– J.G.
Mar 23 at 16:16
1
$begingroup$
@avan1235: the rule of substitution in limits is as follows: if $lim_xto a f(x) =L$ and $lim_xto b g(x) =a$ and $g(x) neq a$ as $xto b$ then $$lim_xto b f(g(x)) =L=lim_xto a f(x) $$ Here $g(x)=xsin x, a=b=0$.
$endgroup$
– Paramanand Singh
Mar 24 at 3:24
|
show 1 more comment
$begingroup$
The function you want to compute the limit of is even, so you can as well consider the limit for $xto0^+$.
Consider the function $f(x)=xsin x$, defined and positive in a some interval $(0,delta)$, has limit $0$ for $xto0^+$ and $f'(x)=sin x+xcos x$. Thus we can assume $f'(x)>0$ over $(0,delta)$. Thus $f$ is continuous and invertible over $(0,delta)$ and therefore the substitution $u=xsin x$ is possible. Then
$$
lim_xto 0^+left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
=lim_uto0^+fracu-tan uu^2tan u
$$
which is easy if you recall that
$$
tan u=u+frac13u^3+o(u^3)
$$
$endgroup$
add a comment |
Your Answer
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Let $u=xsin x$
$$lim_uto 0left(dfrac1utan u-dfrac1u^2right)=lim_uto 0dfracu-tan uu^2tan u$$
Can you proceed?
$endgroup$
1
$begingroup$
I've corrected some errors, but the conversion back to $x$-space is unnecessary.
$endgroup$
– J.G.
Mar 23 at 16:13
$begingroup$
I'll remove that then @J.G.Thanks. Cheers :))
$endgroup$
– Paras Khosla
Mar 23 at 16:13
$begingroup$
Thanks, whats the official arguemnt to change $xsin(x)$ to $u$?
$endgroup$
– avan1235
Mar 23 at 16:14
2
$begingroup$
@avan1235 $lim_xto af(g(x))=lim_utolim_xto ag(x)f(u)$ provided $lim_xto ag(x)$ exists.
$endgroup$
– J.G.
Mar 23 at 16:16
1
$begingroup$
@avan1235: the rule of substitution in limits is as follows: if $lim_xto a f(x) =L$ and $lim_xto b g(x) =a$ and $g(x) neq a$ as $xto b$ then $$lim_xto b f(g(x)) =L=lim_xto a f(x) $$ Here $g(x)=xsin x, a=b=0$.
$endgroup$
– Paramanand Singh
Mar 24 at 3:24
|
show 1 more comment
$begingroup$
Let $u=xsin x$
$$lim_uto 0left(dfrac1utan u-dfrac1u^2right)=lim_uto 0dfracu-tan uu^2tan u$$
Can you proceed?
$endgroup$
1
$begingroup$
I've corrected some errors, but the conversion back to $x$-space is unnecessary.
$endgroup$
– J.G.
Mar 23 at 16:13
$begingroup$
I'll remove that then @J.G.Thanks. Cheers :))
$endgroup$
– Paras Khosla
Mar 23 at 16:13
$begingroup$
Thanks, whats the official arguemnt to change $xsin(x)$ to $u$?
$endgroup$
– avan1235
Mar 23 at 16:14
2
$begingroup$
@avan1235 $lim_xto af(g(x))=lim_utolim_xto ag(x)f(u)$ provided $lim_xto ag(x)$ exists.
$endgroup$
– J.G.
Mar 23 at 16:16
1
$begingroup$
@avan1235: the rule of substitution in limits is as follows: if $lim_xto a f(x) =L$ and $lim_xto b g(x) =a$ and $g(x) neq a$ as $xto b$ then $$lim_xto b f(g(x)) =L=lim_xto a f(x) $$ Here $g(x)=xsin x, a=b=0$.
$endgroup$
– Paramanand Singh
Mar 24 at 3:24
|
show 1 more comment
$begingroup$
Let $u=xsin x$
$$lim_uto 0left(dfrac1utan u-dfrac1u^2right)=lim_uto 0dfracu-tan uu^2tan u$$
Can you proceed?
$endgroup$
Let $u=xsin x$
$$lim_uto 0left(dfrac1utan u-dfrac1u^2right)=lim_uto 0dfracu-tan uu^2tan u$$
Can you proceed?
edited Mar 23 at 16:14
answered Mar 23 at 16:08
Paras KhoslaParas Khosla
3,173626
3,173626
1
$begingroup$
I've corrected some errors, but the conversion back to $x$-space is unnecessary.
$endgroup$
– J.G.
Mar 23 at 16:13
$begingroup$
I'll remove that then @J.G.Thanks. Cheers :))
$endgroup$
– Paras Khosla
Mar 23 at 16:13
$begingroup$
Thanks, whats the official arguemnt to change $xsin(x)$ to $u$?
$endgroup$
– avan1235
Mar 23 at 16:14
2
$begingroup$
@avan1235 $lim_xto af(g(x))=lim_utolim_xto ag(x)f(u)$ provided $lim_xto ag(x)$ exists.
$endgroup$
– J.G.
Mar 23 at 16:16
1
$begingroup$
@avan1235: the rule of substitution in limits is as follows: if $lim_xto a f(x) =L$ and $lim_xto b g(x) =a$ and $g(x) neq a$ as $xto b$ then $$lim_xto b f(g(x)) =L=lim_xto a f(x) $$ Here $g(x)=xsin x, a=b=0$.
$endgroup$
– Paramanand Singh
Mar 24 at 3:24
|
show 1 more comment
1
$begingroup$
I've corrected some errors, but the conversion back to $x$-space is unnecessary.
$endgroup$
– J.G.
Mar 23 at 16:13
$begingroup$
I'll remove that then @J.G.Thanks. Cheers :))
$endgroup$
– Paras Khosla
Mar 23 at 16:13
$begingroup$
Thanks, whats the official arguemnt to change $xsin(x)$ to $u$?
$endgroup$
– avan1235
Mar 23 at 16:14
2
$begingroup$
@avan1235 $lim_xto af(g(x))=lim_utolim_xto ag(x)f(u)$ provided $lim_xto ag(x)$ exists.
$endgroup$
– J.G.
Mar 23 at 16:16
1
$begingroup$
@avan1235: the rule of substitution in limits is as follows: if $lim_xto a f(x) =L$ and $lim_xto b g(x) =a$ and $g(x) neq a$ as $xto b$ then $$lim_xto b f(g(x)) =L=lim_xto a f(x) $$ Here $g(x)=xsin x, a=b=0$.
$endgroup$
– Paramanand Singh
Mar 24 at 3:24
1
1
$begingroup$
I've corrected some errors, but the conversion back to $x$-space is unnecessary.
$endgroup$
– J.G.
Mar 23 at 16:13
$begingroup$
I've corrected some errors, but the conversion back to $x$-space is unnecessary.
$endgroup$
– J.G.
Mar 23 at 16:13
$begingroup$
I'll remove that then @J.G.Thanks. Cheers :))
$endgroup$
– Paras Khosla
Mar 23 at 16:13
$begingroup$
I'll remove that then @J.G.Thanks. Cheers :))
$endgroup$
– Paras Khosla
Mar 23 at 16:13
$begingroup$
Thanks, whats the official arguemnt to change $xsin(x)$ to $u$?
$endgroup$
– avan1235
Mar 23 at 16:14
$begingroup$
Thanks, whats the official arguemnt to change $xsin(x)$ to $u$?
$endgroup$
– avan1235
Mar 23 at 16:14
2
2
$begingroup$
@avan1235 $lim_xto af(g(x))=lim_utolim_xto ag(x)f(u)$ provided $lim_xto ag(x)$ exists.
$endgroup$
– J.G.
Mar 23 at 16:16
$begingroup$
@avan1235 $lim_xto af(g(x))=lim_utolim_xto ag(x)f(u)$ provided $lim_xto ag(x)$ exists.
$endgroup$
– J.G.
Mar 23 at 16:16
1
1
$begingroup$
@avan1235: the rule of substitution in limits is as follows: if $lim_xto a f(x) =L$ and $lim_xto b g(x) =a$ and $g(x) neq a$ as $xto b$ then $$lim_xto b f(g(x)) =L=lim_xto a f(x) $$ Here $g(x)=xsin x, a=b=0$.
$endgroup$
– Paramanand Singh
Mar 24 at 3:24
$begingroup$
@avan1235: the rule of substitution in limits is as follows: if $lim_xto a f(x) =L$ and $lim_xto b g(x) =a$ and $g(x) neq a$ as $xto b$ then $$lim_xto b f(g(x)) =L=lim_xto a f(x) $$ Here $g(x)=xsin x, a=b=0$.
$endgroup$
– Paramanand Singh
Mar 24 at 3:24
|
show 1 more comment
$begingroup$
The function you want to compute the limit of is even, so you can as well consider the limit for $xto0^+$.
Consider the function $f(x)=xsin x$, defined and positive in a some interval $(0,delta)$, has limit $0$ for $xto0^+$ and $f'(x)=sin x+xcos x$. Thus we can assume $f'(x)>0$ over $(0,delta)$. Thus $f$ is continuous and invertible over $(0,delta)$ and therefore the substitution $u=xsin x$ is possible. Then
$$
lim_xto 0^+left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
=lim_uto0^+fracu-tan uu^2tan u
$$
which is easy if you recall that
$$
tan u=u+frac13u^3+o(u^3)
$$
$endgroup$
add a comment |
$begingroup$
The function you want to compute the limit of is even, so you can as well consider the limit for $xto0^+$.
Consider the function $f(x)=xsin x$, defined and positive in a some interval $(0,delta)$, has limit $0$ for $xto0^+$ and $f'(x)=sin x+xcos x$. Thus we can assume $f'(x)>0$ over $(0,delta)$. Thus $f$ is continuous and invertible over $(0,delta)$ and therefore the substitution $u=xsin x$ is possible. Then
$$
lim_xto 0^+left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
=lim_uto0^+fracu-tan uu^2tan u
$$
which is easy if you recall that
$$
tan u=u+frac13u^3+o(u^3)
$$
$endgroup$
add a comment |
$begingroup$
The function you want to compute the limit of is even, so you can as well consider the limit for $xto0^+$.
Consider the function $f(x)=xsin x$, defined and positive in a some interval $(0,delta)$, has limit $0$ for $xto0^+$ and $f'(x)=sin x+xcos x$. Thus we can assume $f'(x)>0$ over $(0,delta)$. Thus $f$ is continuous and invertible over $(0,delta)$ and therefore the substitution $u=xsin x$ is possible. Then
$$
lim_xto 0^+left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
=lim_uto0^+fracu-tan uu^2tan u
$$
which is easy if you recall that
$$
tan u=u+frac13u^3+o(u^3)
$$
$endgroup$
The function you want to compute the limit of is even, so you can as well consider the limit for $xto0^+$.
Consider the function $f(x)=xsin x$, defined and positive in a some interval $(0,delta)$, has limit $0$ for $xto0^+$ and $f'(x)=sin x+xcos x$. Thus we can assume $f'(x)>0$ over $(0,delta)$. Thus $f$ is continuous and invertible over $(0,delta)$ and therefore the substitution $u=xsin x$ is possible. Then
$$
lim_xto 0^+left( frac1xsin(x)tan(xsin(x))-frac1x^2sin^2(x) right)
=lim_uto0^+fracu-tan uu^2tan u
$$
which is easy if you recall that
$$
tan u=u+frac13u^3+o(u^3)
$$
answered Mar 23 at 16:37
egregegreg
185k1486208
185k1486208
add a comment |
add a comment |
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