How can I prove $frac{t-arctan(t)}{t^3}=frac{1}{3(1+c^2)}$ using Rolle's theorem?
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For all $t>0$, there exists $cin]0,t[$ such that
$$frac{t-arctan(t)}{t^3}=frac{1}{3(1+c^2)}$$
Thanks in advance.
analysis rolles-theorem
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up vote
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favorite
For all $t>0$, there exists $cin]0,t[$ such that
$$frac{t-arctan(t)}{t^3}=frac{1}{3(1+c^2)}$$
Thanks in advance.
analysis rolles-theorem
New contributor
What have you already tried? Try editing your question to show this in order to get the most appropriate answers
– MRobinson
yesterday
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up vote
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down vote
favorite
up vote
0
down vote
favorite
For all $t>0$, there exists $cin]0,t[$ such that
$$frac{t-arctan(t)}{t^3}=frac{1}{3(1+c^2)}$$
Thanks in advance.
analysis rolles-theorem
New contributor
For all $t>0$, there exists $cin]0,t[$ such that
$$frac{t-arctan(t)}{t^3}=frac{1}{3(1+c^2)}$$
Thanks in advance.
analysis rolles-theorem
analysis rolles-theorem
New contributor
New contributor
edited yesterday
Nosrati
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25.8k62252
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onzepattes
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What have you already tried? Try editing your question to show this in order to get the most appropriate answers
– MRobinson
yesterday
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What have you already tried? Try editing your question to show this in order to get the most appropriate answers
– MRobinson
yesterday
What have you already tried? Try editing your question to show this in order to get the most appropriate answers
– MRobinson
yesterday
What have you already tried? Try editing your question to show this in order to get the most appropriate answers
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yesterday
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2 Answers
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Hint: I think you mean Cauchy mean value theorem
$$dfrac{f(b)-f(a)}{g(b)-g(a)}=dfrac{f'(c)}{g'(c)}$$
let $f(t)=t-arctan t$ and $g(t)=t^3$.
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Hint:
If $f$ is differentiable in $[0,t]$ then define $g(x)=x[f(x)-f(t)]$ for $xin[0,t]$. Then you can apply Rolle's theorem to $g$.
This would imply that $f(x)=$frac{x-arctan(x)}{x^3}. Bu this is precisely the function we want to get rid off in the first place!!
– onzepattes
yesterday
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
Hint: I think you mean Cauchy mean value theorem
$$dfrac{f(b)-f(a)}{g(b)-g(a)}=dfrac{f'(c)}{g'(c)}$$
let $f(t)=t-arctan t$ and $g(t)=t^3$.
add a comment |
up vote
1
down vote
Hint: I think you mean Cauchy mean value theorem
$$dfrac{f(b)-f(a)}{g(b)-g(a)}=dfrac{f'(c)}{g'(c)}$$
let $f(t)=t-arctan t$ and $g(t)=t^3$.
add a comment |
up vote
1
down vote
up vote
1
down vote
Hint: I think you mean Cauchy mean value theorem
$$dfrac{f(b)-f(a)}{g(b)-g(a)}=dfrac{f'(c)}{g'(c)}$$
let $f(t)=t-arctan t$ and $g(t)=t^3$.
Hint: I think you mean Cauchy mean value theorem
$$dfrac{f(b)-f(a)}{g(b)-g(a)}=dfrac{f'(c)}{g'(c)}$$
let $f(t)=t-arctan t$ and $g(t)=t^3$.
answered yesterday
Nosrati
25.8k62252
25.8k62252
add a comment |
add a comment |
up vote
0
down vote
Hint:
If $f$ is differentiable in $[0,t]$ then define $g(x)=x[f(x)-f(t)]$ for $xin[0,t]$. Then you can apply Rolle's theorem to $g$.
This would imply that $f(x)=$frac{x-arctan(x)}{x^3}. Bu this is precisely the function we want to get rid off in the first place!!
– onzepattes
yesterday
add a comment |
up vote
0
down vote
Hint:
If $f$ is differentiable in $[0,t]$ then define $g(x)=x[f(x)-f(t)]$ for $xin[0,t]$. Then you can apply Rolle's theorem to $g$.
This would imply that $f(x)=$frac{x-arctan(x)}{x^3}. Bu this is precisely the function we want to get rid off in the first place!!
– onzepattes
yesterday
add a comment |
up vote
0
down vote
up vote
0
down vote
Hint:
If $f$ is differentiable in $[0,t]$ then define $g(x)=x[f(x)-f(t)]$ for $xin[0,t]$. Then you can apply Rolle's theorem to $g$.
Hint:
If $f$ is differentiable in $[0,t]$ then define $g(x)=x[f(x)-f(t)]$ for $xin[0,t]$. Then you can apply Rolle's theorem to $g$.
answered yesterday
ajotatxe
52.1k23688
52.1k23688
This would imply that $f(x)=$frac{x-arctan(x)}{x^3}. Bu this is precisely the function we want to get rid off in the first place!!
– onzepattes
yesterday
add a comment |
This would imply that $f(x)=$frac{x-arctan(x)}{x^3}. Bu this is precisely the function we want to get rid off in the first place!!
– onzepattes
yesterday
This would imply that $f(x)=$frac{x-arctan(x)}{x^3}. Bu this is precisely the function we want to get rid off in the first place!!
– onzepattes
yesterday
This would imply that $f(x)=$frac{x-arctan(x)}{x^3}. Bu this is precisely the function we want to get rid off in the first place!!
– onzepattes
yesterday
add a comment |
onzepattes is a new contributor. Be nice, and check out our Code of Conduct.
onzepattes is a new contributor. Be nice, and check out our Code of Conduct.
onzepattes is a new contributor. Be nice, and check out our Code of Conduct.
onzepattes is a new contributor. Be nice, and check out our Code of Conduct.
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