Evaluating the limit for a point on the curve

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For point p(a,b) lying on the curve $2xy^2dx + 2x^2 y dy -
tan(x^2y^2) dx =0 $
;



$lim_ato -inftyb =? $



Options are:

a) $ 0$



b) $-1 $



c) $1$



d) does not exist.




Attempt:



If we observe carefully we get:



$d(x^2 y^2) = tan(x^2 y^2) dx$



$implies ln(csin x^2y^2) = x$



$implies c sin (x^2 y^2) = e^x$



Now clearly as $x to -infty ~ , e^x to 0$, so clearly $y to 0$



But answer given is d. Please let me know my mistake.










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    For point p(a,b) lying on the curve $2xy^2dx + 2x^2 y dy -
    tan(x^2y^2) dx =0 $
    ;



    $lim_ato -inftyb =? $



    Options are:

    a) $ 0$



    b) $-1 $



    c) $1$



    d) does not exist.




    Attempt:



    If we observe carefully we get:



    $d(x^2 y^2) = tan(x^2 y^2) dx$



    $implies ln(csin x^2y^2) = x$



    $implies c sin (x^2 y^2) = e^x$



    Now clearly as $x to -infty ~ , e^x to 0$, so clearly $y to 0$



    But answer given is d. Please let me know my mistake.










    share|cite























      up vote
      5
      down vote

      favorite
      1









      up vote
      5
      down vote

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      1






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      For point p(a,b) lying on the curve $2xy^2dx + 2x^2 y dy -
      tan(x^2y^2) dx =0 $
      ;



      $lim_ato -inftyb =? $



      Options are:

      a) $ 0$



      b) $-1 $



      c) $1$



      d) does not exist.




      Attempt:



      If we observe carefully we get:



      $d(x^2 y^2) = tan(x^2 y^2) dx$



      $implies ln(csin x^2y^2) = x$



      $implies c sin (x^2 y^2) = e^x$



      Now clearly as $x to -infty ~ , e^x to 0$, so clearly $y to 0$



      But answer given is d. Please let me know my mistake.










      share|cite














      For point p(a,b) lying on the curve $2xy^2dx + 2x^2 y dy -
      tan(x^2y^2) dx =0 $
      ;



      $lim_ato -inftyb =? $



      Options are:

      a) $ 0$



      b) $-1 $



      c) $1$



      d) does not exist.




      Attempt:



      If we observe carefully we get:



      $d(x^2 y^2) = tan(x^2 y^2) dx$



      $implies ln(csin x^2y^2) = x$



      $implies c sin (x^2 y^2) = e^x$



      Now clearly as $x to -infty ~ , e^x to 0$, so clearly $y to 0$



      But answer given is d. Please let me know my mistake.







      calculus






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      asked 37 mins ago









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          1 Answer
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          We have the following line:



          $$c sin (x^2 y^2) = e^x$$



          The problem is that $arcsin$ return only a single branch of $sin$, not all of them:



          Now, $c sin (x^2 y^2) = e^x$ gives $$sin (x^2 y^2) = frace^xcimplies x^2 y^2=arcsinleft(frace^xcright)colorred+2kpi\implies y=pmfrac1xsqrtarcsinleft(frace^xcright)colorred+2kpi$$So you have more then a single value for $y$ for any fixed $x$ and the answered are as big as we want so the limit won't get rid from them. So the limit is undefined






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            1 Answer
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            up vote
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            down vote













            We have the following line:



            $$c sin (x^2 y^2) = e^x$$



            The problem is that $arcsin$ return only a single branch of $sin$, not all of them:



            Now, $c sin (x^2 y^2) = e^x$ gives $$sin (x^2 y^2) = frace^xcimplies x^2 y^2=arcsinleft(frace^xcright)colorred+2kpi\implies y=pmfrac1xsqrtarcsinleft(frace^xcright)colorred+2kpi$$So you have more then a single value for $y$ for any fixed $x$ and the answered are as big as we want so the limit won't get rid from them. So the limit is undefined






            share|cite|improve this answer
























              up vote
              3
              down vote













              We have the following line:



              $$c sin (x^2 y^2) = e^x$$



              The problem is that $arcsin$ return only a single branch of $sin$, not all of them:



              Now, $c sin (x^2 y^2) = e^x$ gives $$sin (x^2 y^2) = frace^xcimplies x^2 y^2=arcsinleft(frace^xcright)colorred+2kpi\implies y=pmfrac1xsqrtarcsinleft(frace^xcright)colorred+2kpi$$So you have more then a single value for $y$ for any fixed $x$ and the answered are as big as we want so the limit won't get rid from them. So the limit is undefined






              share|cite|improve this answer






















                up vote
                3
                down vote










                up vote
                3
                down vote









                We have the following line:



                $$c sin (x^2 y^2) = e^x$$



                The problem is that $arcsin$ return only a single branch of $sin$, not all of them:



                Now, $c sin (x^2 y^2) = e^x$ gives $$sin (x^2 y^2) = frace^xcimplies x^2 y^2=arcsinleft(frace^xcright)colorred+2kpi\implies y=pmfrac1xsqrtarcsinleft(frace^xcright)colorred+2kpi$$So you have more then a single value for $y$ for any fixed $x$ and the answered are as big as we want so the limit won't get rid from them. So the limit is undefined






                share|cite|improve this answer












                We have the following line:



                $$c sin (x^2 y^2) = e^x$$



                The problem is that $arcsin$ return only a single branch of $sin$, not all of them:



                Now, $c sin (x^2 y^2) = e^x$ gives $$sin (x^2 y^2) = frace^xcimplies x^2 y^2=arcsinleft(frace^xcright)colorred+2kpi\implies y=pmfrac1xsqrtarcsinleft(frace^xcright)colorred+2kpi$$So you have more then a single value for $y$ for any fixed $x$ and the answered are as big as we want so the limit won't get rid from them. So the limit is undefined







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered 24 mins ago









                Holo

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