Find and classify the stationary points of $y = x^ 2/(x-4)$












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$begingroup$


I have already obtained the answer by using the quotient rule and so there are stationary points at x = 0 and x = 8. I am fine at doing these types of questions but I don't fully understand the meaning behind the answer. This was also provided in the solution of the answer



Now y approaches infinity as x approaches infinity, and
y approaches infinity as x approaches 4^(+). Hence, x = 8 must be a minimum. Similarly, y approaches (-)infinity as x approaches (-)infinity
and as x approaches 4^(-). Hence x = 0 is a maximum.



How do you know that x=8 is a maximum and x=0 is a minimum also what does the 4^(+) and 4^(-) mean ? sorry if this is a silly question I just don't get what the final answer says.










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$endgroup$

















    0












    $begingroup$


    I have already obtained the answer by using the quotient rule and so there are stationary points at x = 0 and x = 8. I am fine at doing these types of questions but I don't fully understand the meaning behind the answer. This was also provided in the solution of the answer



    Now y approaches infinity as x approaches infinity, and
    y approaches infinity as x approaches 4^(+). Hence, x = 8 must be a minimum. Similarly, y approaches (-)infinity as x approaches (-)infinity
    and as x approaches 4^(-). Hence x = 0 is a maximum.



    How do you know that x=8 is a maximum and x=0 is a minimum also what does the 4^(+) and 4^(-) mean ? sorry if this is a silly question I just don't get what the final answer says.










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      I have already obtained the answer by using the quotient rule and so there are stationary points at x = 0 and x = 8. I am fine at doing these types of questions but I don't fully understand the meaning behind the answer. This was also provided in the solution of the answer



      Now y approaches infinity as x approaches infinity, and
      y approaches infinity as x approaches 4^(+). Hence, x = 8 must be a minimum. Similarly, y approaches (-)infinity as x approaches (-)infinity
      and as x approaches 4^(-). Hence x = 0 is a maximum.



      How do you know that x=8 is a maximum and x=0 is a minimum also what does the 4^(+) and 4^(-) mean ? sorry if this is a silly question I just don't get what the final answer says.










      share|cite|improve this question











      $endgroup$




      I have already obtained the answer by using the quotient rule and so there are stationary points at x = 0 and x = 8. I am fine at doing these types of questions but I don't fully understand the meaning behind the answer. This was also provided in the solution of the answer



      Now y approaches infinity as x approaches infinity, and
      y approaches infinity as x approaches 4^(+). Hence, x = 8 must be a minimum. Similarly, y approaches (-)infinity as x approaches (-)infinity
      and as x approaches 4^(-). Hence x = 0 is a maximum.



      How do you know that x=8 is a maximum and x=0 is a minimum also what does the 4^(+) and 4^(-) mean ? sorry if this is a silly question I just don't get what the final answer says.







      stationary-point






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      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 15 at 16:54









      David G. Stork

      11k41432




      11k41432










      asked Jan 15 at 1:33









      CinnaCinna

      122




      122






















          1 Answer
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          $begingroup$

          Take the second derivatives to determine whether a function is maximized or minimized at a point.



          $4^+$ means approaching the point $4$ from above.



          enter image description here






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            if it is $y=frac{x^2}{x-4}$ it is a hyperbola with one vertical and one slanted asymptote. For some reason we've had several in the past few days
            $endgroup$
            – Will Jagy
            Jan 15 at 2:32










          • $begingroup$
            Okay thanks for the help I understand it now.
            $endgroup$
            – Cinna
            Jan 16 at 2:07











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          1 Answer
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          active

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          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0












          $begingroup$

          Take the second derivatives to determine whether a function is maximized or minimized at a point.



          $4^+$ means approaching the point $4$ from above.



          enter image description here






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            if it is $y=frac{x^2}{x-4}$ it is a hyperbola with one vertical and one slanted asymptote. For some reason we've had several in the past few days
            $endgroup$
            – Will Jagy
            Jan 15 at 2:32










          • $begingroup$
            Okay thanks for the help I understand it now.
            $endgroup$
            – Cinna
            Jan 16 at 2:07
















          0












          $begingroup$

          Take the second derivatives to determine whether a function is maximized or minimized at a point.



          $4^+$ means approaching the point $4$ from above.



          enter image description here






          share|cite|improve this answer











          $endgroup$













          • $begingroup$
            if it is $y=frac{x^2}{x-4}$ it is a hyperbola with one vertical and one slanted asymptote. For some reason we've had several in the past few days
            $endgroup$
            – Will Jagy
            Jan 15 at 2:32










          • $begingroup$
            Okay thanks for the help I understand it now.
            $endgroup$
            – Cinna
            Jan 16 at 2:07














          0












          0








          0





          $begingroup$

          Take the second derivatives to determine whether a function is maximized or minimized at a point.



          $4^+$ means approaching the point $4$ from above.



          enter image description here






          share|cite|improve this answer











          $endgroup$



          Take the second derivatives to determine whether a function is maximized or minimized at a point.



          $4^+$ means approaching the point $4$ from above.



          enter image description here







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Jan 15 at 1:52

























          answered Jan 15 at 1:44









          David G. StorkDavid G. Stork

          11k41432




          11k41432












          • $begingroup$
            if it is $y=frac{x^2}{x-4}$ it is a hyperbola with one vertical and one slanted asymptote. For some reason we've had several in the past few days
            $endgroup$
            – Will Jagy
            Jan 15 at 2:32










          • $begingroup$
            Okay thanks for the help I understand it now.
            $endgroup$
            – Cinna
            Jan 16 at 2:07


















          • $begingroup$
            if it is $y=frac{x^2}{x-4}$ it is a hyperbola with one vertical and one slanted asymptote. For some reason we've had several in the past few days
            $endgroup$
            – Will Jagy
            Jan 15 at 2:32










          • $begingroup$
            Okay thanks for the help I understand it now.
            $endgroup$
            – Cinna
            Jan 16 at 2:07
















          $begingroup$
          if it is $y=frac{x^2}{x-4}$ it is a hyperbola with one vertical and one slanted asymptote. For some reason we've had several in the past few days
          $endgroup$
          – Will Jagy
          Jan 15 at 2:32




          $begingroup$
          if it is $y=frac{x^2}{x-4}$ it is a hyperbola with one vertical and one slanted asymptote. For some reason we've had several in the past few days
          $endgroup$
          – Will Jagy
          Jan 15 at 2:32












          $begingroup$
          Okay thanks for the help I understand it now.
          $endgroup$
          – Cinna
          Jan 16 at 2:07




          $begingroup$
          Okay thanks for the help I understand it now.
          $endgroup$
          – Cinna
          Jan 16 at 2:07


















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