Comparing two infinitely large functions












0












$begingroup$


I have $ f(x)=frac{x*arctgx}{sqrt{4x+3}} $
And $ g(x)=sqrt x - {x}^{1/3} $



Limits of both functions are infinity, so these functions are infinitely large .



I need to write equivalent functions for both as $ C{x}^{n} $ and find out order of growth/smallness of functions and then compare f(x) and g(x).



I don't no how to write equivalent for f(x) and what are common ideas of tasks like this, in my lecture copybook I didn't find anything/










share|cite|improve this question











$endgroup$

















    0












    $begingroup$


    I have $ f(x)=frac{x*arctgx}{sqrt{4x+3}} $
    And $ g(x)=sqrt x - {x}^{1/3} $



    Limits of both functions are infinity, so these functions are infinitely large .



    I need to write equivalent functions for both as $ C{x}^{n} $ and find out order of growth/smallness of functions and then compare f(x) and g(x).



    I don't no how to write equivalent for f(x) and what are common ideas of tasks like this, in my lecture copybook I didn't find anything/










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      I have $ f(x)=frac{x*arctgx}{sqrt{4x+3}} $
      And $ g(x)=sqrt x - {x}^{1/3} $



      Limits of both functions are infinity, so these functions are infinitely large .



      I need to write equivalent functions for both as $ C{x}^{n} $ and find out order of growth/smallness of functions and then compare f(x) and g(x).



      I don't no how to write equivalent for f(x) and what are common ideas of tasks like this, in my lecture copybook I didn't find anything/










      share|cite|improve this question











      $endgroup$




      I have $ f(x)=frac{x*arctgx}{sqrt{4x+3}} $
      And $ g(x)=sqrt x - {x}^{1/3} $



      Limits of both functions are infinity, so these functions are infinitely large .



      I need to write equivalent functions for both as $ C{x}^{n} $ and find out order of growth/smallness of functions and then compare f(x) and g(x).



      I don't no how to write equivalent for f(x) and what are common ideas of tasks like this, in my lecture copybook I didn't find anything/







      calculus limits functions






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 16 at 9:10









      MaoWao

      3,318617




      3,318617










      asked Jan 16 at 8:48









      TovarischTovarisch

      297




      297






















          1 Answer
          1






          active

          oldest

          votes


















          1












          $begingroup$

          $f(x)=x^{1/2} frac {arctan (x)} {sqrt {4+frac 3 x}}$ and $g(x)=x^{1/2} (1-x^{frac 1 3 -frac 1 2})$. So both functions behave like $x^{1/2}$ when $x to infty$ and $lim frac {f(x)} {g(x)}=frac {pi} 4$ as $x to infty$.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            I guess you forgot a square root in the denominator of $f(x)$. Then the limit will be $pi/4$.
            $endgroup$
            – Toffomat
            Jan 16 at 9:30










          • $begingroup$
            @Toffomat Right. Thanks for pointing out.
            $endgroup$
            – Kavi Rama Murthy
            Jan 16 at 9:32











          Your Answer





          StackExchange.ifUsing("editor", function () {
          return StackExchange.using("mathjaxEditing", function () {
          StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
          StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
          });
          });
          }, "mathjax-editing");

          StackExchange.ready(function() {
          var channelOptions = {
          tags: "".split(" "),
          id: "69"
          };
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function() {
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled) {
          StackExchange.using("snippets", function() {
          createEditor();
          });
          }
          else {
          createEditor();
          }
          });

          function createEditor() {
          StackExchange.prepareEditor({
          heartbeatType: 'answer',
          autoActivateHeartbeat: false,
          convertImagesToLinks: true,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          noCode: true, onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          });


          }
          });














          draft saved

          draft discarded


















          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3075487%2fcomparing-two-infinitely-large-functions%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          1












          $begingroup$

          $f(x)=x^{1/2} frac {arctan (x)} {sqrt {4+frac 3 x}}$ and $g(x)=x^{1/2} (1-x^{frac 1 3 -frac 1 2})$. So both functions behave like $x^{1/2}$ when $x to infty$ and $lim frac {f(x)} {g(x)}=frac {pi} 4$ as $x to infty$.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            I guess you forgot a square root in the denominator of $f(x)$. Then the limit will be $pi/4$.
            $endgroup$
            – Toffomat
            Jan 16 at 9:30










          • $begingroup$
            @Toffomat Right. Thanks for pointing out.
            $endgroup$
            – Kavi Rama Murthy
            Jan 16 at 9:32
















          1












          $begingroup$

          $f(x)=x^{1/2} frac {arctan (x)} {sqrt {4+frac 3 x}}$ and $g(x)=x^{1/2} (1-x^{frac 1 3 -frac 1 2})$. So both functions behave like $x^{1/2}$ when $x to infty$ and $lim frac {f(x)} {g(x)}=frac {pi} 4$ as $x to infty$.






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            I guess you forgot a square root in the denominator of $f(x)$. Then the limit will be $pi/4$.
            $endgroup$
            – Toffomat
            Jan 16 at 9:30










          • $begingroup$
            @Toffomat Right. Thanks for pointing out.
            $endgroup$
            – Kavi Rama Murthy
            Jan 16 at 9:32














          1












          1








          1





          $begingroup$

          $f(x)=x^{1/2} frac {arctan (x)} {sqrt {4+frac 3 x}}$ and $g(x)=x^{1/2} (1-x^{frac 1 3 -frac 1 2})$. So both functions behave like $x^{1/2}$ when $x to infty$ and $lim frac {f(x)} {g(x)}=frac {pi} 4$ as $x to infty$.






          share|cite|improve this answer











          $endgroup$



          $f(x)=x^{1/2} frac {arctan (x)} {sqrt {4+frac 3 x}}$ and $g(x)=x^{1/2} (1-x^{frac 1 3 -frac 1 2})$. So both functions behave like $x^{1/2}$ when $x to infty$ and $lim frac {f(x)} {g(x)}=frac {pi} 4$ as $x to infty$.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Jan 16 at 9:31

























          answered Jan 16 at 8:53









          Kavi Rama MurthyKavi Rama Murthy

          61.7k42262




          61.7k42262












          • $begingroup$
            I guess you forgot a square root in the denominator of $f(x)$. Then the limit will be $pi/4$.
            $endgroup$
            – Toffomat
            Jan 16 at 9:30










          • $begingroup$
            @Toffomat Right. Thanks for pointing out.
            $endgroup$
            – Kavi Rama Murthy
            Jan 16 at 9:32


















          • $begingroup$
            I guess you forgot a square root in the denominator of $f(x)$. Then the limit will be $pi/4$.
            $endgroup$
            – Toffomat
            Jan 16 at 9:30










          • $begingroup$
            @Toffomat Right. Thanks for pointing out.
            $endgroup$
            – Kavi Rama Murthy
            Jan 16 at 9:32
















          $begingroup$
          I guess you forgot a square root in the denominator of $f(x)$. Then the limit will be $pi/4$.
          $endgroup$
          – Toffomat
          Jan 16 at 9:30




          $begingroup$
          I guess you forgot a square root in the denominator of $f(x)$. Then the limit will be $pi/4$.
          $endgroup$
          – Toffomat
          Jan 16 at 9:30












          $begingroup$
          @Toffomat Right. Thanks for pointing out.
          $endgroup$
          – Kavi Rama Murthy
          Jan 16 at 9:32




          $begingroup$
          @Toffomat Right. Thanks for pointing out.
          $endgroup$
          – Kavi Rama Murthy
          Jan 16 at 9:32


















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Mathematics Stack Exchange!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          Use MathJax to format equations. MathJax reference.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3075487%2fcomparing-two-infinitely-large-functions%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          MongoDB - Not Authorized To Execute Command

          How to fix TextFormField cause rebuild widget in Flutter

          in spring boot 2.1 many test slices are not allowed anymore due to multiple @BootstrapWith