Are derivative functions always bounded on closed intervals?












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Is it true that if a function is differentiable on a closed interval, then its derivative is bounded on that interval?



I know that by Darboux’s theorem, the derivative cannot tend to infinity, but what if it oscillates and the oscillation tends to infinity?



Thanks in advance!










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    0












    $begingroup$


    Is it true that if a function is differentiable on a closed interval, then its derivative is bounded on that interval?



    I know that by Darboux’s theorem, the derivative cannot tend to infinity, but what if it oscillates and the oscillation tends to infinity?



    Thanks in advance!










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      Is it true that if a function is differentiable on a closed interval, then its derivative is bounded on that interval?



      I know that by Darboux’s theorem, the derivative cannot tend to infinity, but what if it oscillates and the oscillation tends to infinity?



      Thanks in advance!










      share|cite|improve this question









      $endgroup$




      Is it true that if a function is differentiable on a closed interval, then its derivative is bounded on that interval?



      I know that by Darboux’s theorem, the derivative cannot tend to infinity, but what if it oscillates and the oscillation tends to infinity?



      Thanks in advance!







      calculus analysis derivatives






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      asked Jan 9 at 11:54









      JiuJiu

      552113




      552113






















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          $begingroup$

          $f(x)=x^{1.5}sin(frac 1 x)$ for $x neq 0$, $f(0)=0$ is a counter example. Note that $|f'(frac 1 {npi})| to infty$






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            1 Answer
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            active

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            $begingroup$

            $f(x)=x^{1.5}sin(frac 1 x)$ for $x neq 0$, $f(0)=0$ is a counter example. Note that $|f'(frac 1 {npi})| to infty$






            share|cite|improve this answer









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              $begingroup$

              $f(x)=x^{1.5}sin(frac 1 x)$ for $x neq 0$, $f(0)=0$ is a counter example. Note that $|f'(frac 1 {npi})| to infty$






              share|cite|improve this answer









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                $begingroup$

                $f(x)=x^{1.5}sin(frac 1 x)$ for $x neq 0$, $f(0)=0$ is a counter example. Note that $|f'(frac 1 {npi})| to infty$






                share|cite|improve this answer









                $endgroup$



                $f(x)=x^{1.5}sin(frac 1 x)$ for $x neq 0$, $f(0)=0$ is a counter example. Note that $|f'(frac 1 {npi})| to infty$







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                answered Jan 9 at 11:59









                Kavi Rama MurthyKavi Rama Murthy

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