Prove that for every $epsilon>0$, there exists $cin (a,b)$ so that $f(x)(c−a)<epsilon$ for all $xin...












0












$begingroup$



Prove that for every $epsilon>0$, there exists $cin (a,b)$ so that $f(x)(c−a)<epsilon$ for all $xin [a,b]$.




I'm so confused about how to even start this question. I've tried setting $c = (a+b) / 2$, so that it is in the interval but I have no clue what I should even be trying to achieve to get prove this statement.



The question also originally states that $f$ is bounded on $[a, b]$ and that for any $c in (a, b)$, $f$ is integrable on $[c, b]$.



image










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$endgroup$












  • $begingroup$
    I suppose $f$ is a function mapping $[a,b]$ into $mathbb R$, but which properties does it have?
    $endgroup$
    – Mars Plastic
    Feb 3 at 0:19










  • $begingroup$
    f is bounded on [a, b] and that for any c ∈ (a, b), f is integrable on [c, b].
    $endgroup$
    – veloxvictory
    Feb 3 at 0:23










  • $begingroup$
    @veloxvictory please edit your question so that the premises and question are in the body of the main text - it is illegible as written right now...
    $endgroup$
    – Mariah
    Feb 3 at 0:41










  • $begingroup$
    Probably a duplicate of this: math.stackexchange.com/questions/287540/…
    $endgroup$
    – Mars Plastic
    Feb 4 at 23:53
















0












$begingroup$



Prove that for every $epsilon>0$, there exists $cin (a,b)$ so that $f(x)(c−a)<epsilon$ for all $xin [a,b]$.




I'm so confused about how to even start this question. I've tried setting $c = (a+b) / 2$, so that it is in the interval but I have no clue what I should even be trying to achieve to get prove this statement.



The question also originally states that $f$ is bounded on $[a, b]$ and that for any $c in (a, b)$, $f$ is integrable on $[c, b]$.



image










share|cite|improve this question











$endgroup$












  • $begingroup$
    I suppose $f$ is a function mapping $[a,b]$ into $mathbb R$, but which properties does it have?
    $endgroup$
    – Mars Plastic
    Feb 3 at 0:19










  • $begingroup$
    f is bounded on [a, b] and that for any c ∈ (a, b), f is integrable on [c, b].
    $endgroup$
    – veloxvictory
    Feb 3 at 0:23










  • $begingroup$
    @veloxvictory please edit your question so that the premises and question are in the body of the main text - it is illegible as written right now...
    $endgroup$
    – Mariah
    Feb 3 at 0:41










  • $begingroup$
    Probably a duplicate of this: math.stackexchange.com/questions/287540/…
    $endgroup$
    – Mars Plastic
    Feb 4 at 23:53














0












0








0





$begingroup$



Prove that for every $epsilon>0$, there exists $cin (a,b)$ so that $f(x)(c−a)<epsilon$ for all $xin [a,b]$.




I'm so confused about how to even start this question. I've tried setting $c = (a+b) / 2$, so that it is in the interval but I have no clue what I should even be trying to achieve to get prove this statement.



The question also originally states that $f$ is bounded on $[a, b]$ and that for any $c in (a, b)$, $f$ is integrable on $[c, b]$.



image










share|cite|improve this question











$endgroup$





Prove that for every $epsilon>0$, there exists $cin (a,b)$ so that $f(x)(c−a)<epsilon$ for all $xin [a,b]$.




I'm so confused about how to even start this question. I've tried setting $c = (a+b) / 2$, so that it is in the interval but I have no clue what I should even be trying to achieve to get prove this statement.



The question also originally states that $f$ is bounded on $[a, b]$ and that for any $c in (a, b)$, $f$ is integrable on $[c, b]$.



image







real-analysis integration






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share|cite|improve this question













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share|cite|improve this question








edited Feb 5 at 7:02









Brahadeesh

6,51642365




6,51642365










asked Feb 3 at 0:16









veloxvictoryveloxvictory

61




61












  • $begingroup$
    I suppose $f$ is a function mapping $[a,b]$ into $mathbb R$, but which properties does it have?
    $endgroup$
    – Mars Plastic
    Feb 3 at 0:19










  • $begingroup$
    f is bounded on [a, b] and that for any c ∈ (a, b), f is integrable on [c, b].
    $endgroup$
    – veloxvictory
    Feb 3 at 0:23










  • $begingroup$
    @veloxvictory please edit your question so that the premises and question are in the body of the main text - it is illegible as written right now...
    $endgroup$
    – Mariah
    Feb 3 at 0:41










  • $begingroup$
    Probably a duplicate of this: math.stackexchange.com/questions/287540/…
    $endgroup$
    – Mars Plastic
    Feb 4 at 23:53


















  • $begingroup$
    I suppose $f$ is a function mapping $[a,b]$ into $mathbb R$, but which properties does it have?
    $endgroup$
    – Mars Plastic
    Feb 3 at 0:19










  • $begingroup$
    f is bounded on [a, b] and that for any c ∈ (a, b), f is integrable on [c, b].
    $endgroup$
    – veloxvictory
    Feb 3 at 0:23










  • $begingroup$
    @veloxvictory please edit your question so that the premises and question are in the body of the main text - it is illegible as written right now...
    $endgroup$
    – Mariah
    Feb 3 at 0:41










  • $begingroup$
    Probably a duplicate of this: math.stackexchange.com/questions/287540/…
    $endgroup$
    – Mars Plastic
    Feb 4 at 23:53
















$begingroup$
I suppose $f$ is a function mapping $[a,b]$ into $mathbb R$, but which properties does it have?
$endgroup$
– Mars Plastic
Feb 3 at 0:19




$begingroup$
I suppose $f$ is a function mapping $[a,b]$ into $mathbb R$, but which properties does it have?
$endgroup$
– Mars Plastic
Feb 3 at 0:19












$begingroup$
f is bounded on [a, b] and that for any c ∈ (a, b), f is integrable on [c, b].
$endgroup$
– veloxvictory
Feb 3 at 0:23




$begingroup$
f is bounded on [a, b] and that for any c ∈ (a, b), f is integrable on [c, b].
$endgroup$
– veloxvictory
Feb 3 at 0:23












$begingroup$
@veloxvictory please edit your question so that the premises and question are in the body of the main text - it is illegible as written right now...
$endgroup$
– Mariah
Feb 3 at 0:41




$begingroup$
@veloxvictory please edit your question so that the premises and question are in the body of the main text - it is illegible as written right now...
$endgroup$
– Mariah
Feb 3 at 0:41












$begingroup$
Probably a duplicate of this: math.stackexchange.com/questions/287540/…
$endgroup$
– Mars Plastic
Feb 4 at 23:53




$begingroup$
Probably a duplicate of this: math.stackexchange.com/questions/287540/…
$endgroup$
– Mars Plastic
Feb 4 at 23:53










1 Answer
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$begingroup$

If $f$ is bounded, then there is some $Min (0,infty)$ such that $|f(x)|le M$ for all $xin[a,b]$. If you choose any $cin(a,a+epsilon/M)$, you get



$$ f(x)(c-a)le |f(x)|epsilon/Mle epsilon quad text{for all $xin[a,b]$.}$$



However, I doubt that this is the actual question, since this does not need integrability.






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    $begingroup$

    If $f$ is bounded, then there is some $Min (0,infty)$ such that $|f(x)|le M$ for all $xin[a,b]$. If you choose any $cin(a,a+epsilon/M)$, you get



    $$ f(x)(c-a)le |f(x)|epsilon/Mle epsilon quad text{for all $xin[a,b]$.}$$



    However, I doubt that this is the actual question, since this does not need integrability.






    share|cite|improve this answer









    $endgroup$


















      1












      $begingroup$

      If $f$ is bounded, then there is some $Min (0,infty)$ such that $|f(x)|le M$ for all $xin[a,b]$. If you choose any $cin(a,a+epsilon/M)$, you get



      $$ f(x)(c-a)le |f(x)|epsilon/Mle epsilon quad text{for all $xin[a,b]$.}$$



      However, I doubt that this is the actual question, since this does not need integrability.






      share|cite|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        If $f$ is bounded, then there is some $Min (0,infty)$ such that $|f(x)|le M$ for all $xin[a,b]$. If you choose any $cin(a,a+epsilon/M)$, you get



        $$ f(x)(c-a)le |f(x)|epsilon/Mle epsilon quad text{for all $xin[a,b]$.}$$



        However, I doubt that this is the actual question, since this does not need integrability.






        share|cite|improve this answer









        $endgroup$



        If $f$ is bounded, then there is some $Min (0,infty)$ such that $|f(x)|le M$ for all $xin[a,b]$. If you choose any $cin(a,a+epsilon/M)$, you get



        $$ f(x)(c-a)le |f(x)|epsilon/Mle epsilon quad text{for all $xin[a,b]$.}$$



        However, I doubt that this is the actual question, since this does not need integrability.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Feb 3 at 0:38









        Mars PlasticMars Plastic

        1,465122




        1,465122






























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