Find the critical points of $g(x,y) = 4x^3 - 12xy + 3y^2 - 18y -5.$ Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 23, 2019 at 00:00UTC (8:00pm US/Eastern)Find all critical points of $f(x,y) = x^3 - 12xy + 8y^3$ and state maximum, minimum, or saddle points.Conceptual question: Critical PointsFind and classify the critical pointsFinding Critical Points and Local Maxima/Minima or Saddle PointHow would you find and classify ALL of the critical points of a function of 2 variables?Critical points have to be stationary?Find the critical points of the function $f(x,y)=(x^2+y^2)e^y^2-x^2$Determine and classify all critical points of function.Why are there critical points at these points?What is the nature of the critical points of $f(x,y) = 4x^2 -12xy + 9y^2$.

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Find the critical points of $g(x,y) = 4x^3 - 12xy + 3y^2 - 18y -5.$



Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 23, 2019 at 00:00UTC (8:00pm US/Eastern)Find all critical points of $f(x,y) = x^3 - 12xy + 8y^3$ and state maximum, minimum, or saddle points.Conceptual question: Critical PointsFind and classify the critical pointsFinding Critical Points and Local Maxima/Minima or Saddle PointHow would you find and classify ALL of the critical points of a function of 2 variables?Critical points have to be stationary?Find the critical points of the function $f(x,y)=(x^2+y^2)e^y^2-x^2$Determine and classify all critical points of function.Why are there critical points at these points?What is the nature of the critical points of $f(x,y) = 4x^2 -12xy + 9y^2$.










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I have the function $g(x,y) = 4x^3 - 12xy + 3y^2 - 18y -5.$ The only critical points that I have found for this function are $(-1, 1)$, and $(3, 9)$. But my professor insisted that there are more critical points besides these two.



Can anyone help me find them please?










share|cite|improve this question











$endgroup$











  • $begingroup$
    wolfram alpha gives that those two points you list are indeed the only critical points for $g$.
    $endgroup$
    – thesmallprint
    Mar 27 at 19:42










  • $begingroup$
    Okay, thank you. I will tell my professor.
    $endgroup$
    – Uchuuko
    Mar 27 at 19:44










  • $begingroup$
    Why not publish you answer so that it can be inspected closely?
    $endgroup$
    – NoChance
    Mar 27 at 19:59
















0












$begingroup$


I have the function $g(x,y) = 4x^3 - 12xy + 3y^2 - 18y -5.$ The only critical points that I have found for this function are $(-1, 1)$, and $(3, 9)$. But my professor insisted that there are more critical points besides these two.



Can anyone help me find them please?










share|cite|improve this question











$endgroup$











  • $begingroup$
    wolfram alpha gives that those two points you list are indeed the only critical points for $g$.
    $endgroup$
    – thesmallprint
    Mar 27 at 19:42










  • $begingroup$
    Okay, thank you. I will tell my professor.
    $endgroup$
    – Uchuuko
    Mar 27 at 19:44










  • $begingroup$
    Why not publish you answer so that it can be inspected closely?
    $endgroup$
    – NoChance
    Mar 27 at 19:59














0












0








0





$begingroup$


I have the function $g(x,y) = 4x^3 - 12xy + 3y^2 - 18y -5.$ The only critical points that I have found for this function are $(-1, 1)$, and $(3, 9)$. But my professor insisted that there are more critical points besides these two.



Can anyone help me find them please?










share|cite|improve this question











$endgroup$




I have the function $g(x,y) = 4x^3 - 12xy + 3y^2 - 18y -5.$ The only critical points that I have found for this function are $(-1, 1)$, and $(3, 9)$. But my professor insisted that there are more critical points besides these two.



Can anyone help me find them please?







multivariable-calculus partial-derivative






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Mar 27 at 19:37









thesmallprint

2,7101618




2,7101618










asked Mar 27 at 19:34









UchuukoUchuuko

468




468











  • $begingroup$
    wolfram alpha gives that those two points you list are indeed the only critical points for $g$.
    $endgroup$
    – thesmallprint
    Mar 27 at 19:42










  • $begingroup$
    Okay, thank you. I will tell my professor.
    $endgroup$
    – Uchuuko
    Mar 27 at 19:44










  • $begingroup$
    Why not publish you answer so that it can be inspected closely?
    $endgroup$
    – NoChance
    Mar 27 at 19:59

















  • $begingroup$
    wolfram alpha gives that those two points you list are indeed the only critical points for $g$.
    $endgroup$
    – thesmallprint
    Mar 27 at 19:42










  • $begingroup$
    Okay, thank you. I will tell my professor.
    $endgroup$
    – Uchuuko
    Mar 27 at 19:44










  • $begingroup$
    Why not publish you answer so that it can be inspected closely?
    $endgroup$
    – NoChance
    Mar 27 at 19:59
















$begingroup$
wolfram alpha gives that those two points you list are indeed the only critical points for $g$.
$endgroup$
– thesmallprint
Mar 27 at 19:42




$begingroup$
wolfram alpha gives that those two points you list are indeed the only critical points for $g$.
$endgroup$
– thesmallprint
Mar 27 at 19:42












$begingroup$
Okay, thank you. I will tell my professor.
$endgroup$
– Uchuuko
Mar 27 at 19:44




$begingroup$
Okay, thank you. I will tell my professor.
$endgroup$
– Uchuuko
Mar 27 at 19:44












$begingroup$
Why not publish you answer so that it can be inspected closely?
$endgroup$
– NoChance
Mar 27 at 19:59





$begingroup$
Why not publish you answer so that it can be inspected closely?
$endgroup$
– NoChance
Mar 27 at 19:59











1 Answer
1






active

oldest

votes


















1












$begingroup$

The critical points occur where the gradient of the scalar field is zero. In this case



$nabla g(x,y)=(12x^2-12y, 6y-12x-18)=overrightarrow0$



If you solve this system of equations you'll find that the only two points are



$(-1, 1)$ and $(3, 9)$



As a consequence of the Fundamental Theorem of Algebra, these are the only two solutions.






share|cite|improve this answer









$endgroup$












  • $begingroup$
    The system of equations can be interpreted as the intersection of a parabola and line, which can have at most two intersection points.
    $endgroup$
    – amd
    Mar 27 at 20:04











Your Answer








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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









1












$begingroup$

The critical points occur where the gradient of the scalar field is zero. In this case



$nabla g(x,y)=(12x^2-12y, 6y-12x-18)=overrightarrow0$



If you solve this system of equations you'll find that the only two points are



$(-1, 1)$ and $(3, 9)$



As a consequence of the Fundamental Theorem of Algebra, these are the only two solutions.






share|cite|improve this answer









$endgroup$












  • $begingroup$
    The system of equations can be interpreted as the intersection of a parabola and line, which can have at most two intersection points.
    $endgroup$
    – amd
    Mar 27 at 20:04















1












$begingroup$

The critical points occur where the gradient of the scalar field is zero. In this case



$nabla g(x,y)=(12x^2-12y, 6y-12x-18)=overrightarrow0$



If you solve this system of equations you'll find that the only two points are



$(-1, 1)$ and $(3, 9)$



As a consequence of the Fundamental Theorem of Algebra, these are the only two solutions.






share|cite|improve this answer









$endgroup$












  • $begingroup$
    The system of equations can be interpreted as the intersection of a parabola and line, which can have at most two intersection points.
    $endgroup$
    – amd
    Mar 27 at 20:04













1












1








1





$begingroup$

The critical points occur where the gradient of the scalar field is zero. In this case



$nabla g(x,y)=(12x^2-12y, 6y-12x-18)=overrightarrow0$



If you solve this system of equations you'll find that the only two points are



$(-1, 1)$ and $(3, 9)$



As a consequence of the Fundamental Theorem of Algebra, these are the only two solutions.






share|cite|improve this answer









$endgroup$



The critical points occur where the gradient of the scalar field is zero. In this case



$nabla g(x,y)=(12x^2-12y, 6y-12x-18)=overrightarrow0$



If you solve this system of equations you'll find that the only two points are



$(-1, 1)$ and $(3, 9)$



As a consequence of the Fundamental Theorem of Algebra, these are the only two solutions.







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Mar 27 at 20:01









officialnoriaofficialnoria

112




112











  • $begingroup$
    The system of equations can be interpreted as the intersection of a parabola and line, which can have at most two intersection points.
    $endgroup$
    – amd
    Mar 27 at 20:04
















  • $begingroup$
    The system of equations can be interpreted as the intersection of a parabola and line, which can have at most two intersection points.
    $endgroup$
    – amd
    Mar 27 at 20:04















$begingroup$
The system of equations can be interpreted as the intersection of a parabola and line, which can have at most two intersection points.
$endgroup$
– amd
Mar 27 at 20:04




$begingroup$
The system of equations can be interpreted as the intersection of a parabola and line, which can have at most two intersection points.
$endgroup$
– amd
Mar 27 at 20:04

















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