[多變] 再一題二元變數極值

[jjx66os (igor)]

Find all the local maxima,local minima,and saddle point of
G(x,y)= x^3 - x^2 + 3y(x^2) - 4xy - 3(y^3) + (13/2)(y^2)

Gx = 3(x^2) - 2x + 6xy - 4y
Gy = 3(x^2) - 4x - 9(y^2) + 13y

解Gx=Gy=0

   x=?????
   y=?????

請問這該怎麼解呢?

謝謝~

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推 suhorng:Gx=0:x(3x-2)+3y(3x-2)=0→(x+3y)(3x-2)=0
→ suhorng:1.x=2/3代到Gy=0求y 2.x=-3y代到Gy=0求x,y
→ jjx66os:噢噢了解!太感謝你了，幫我解了兩題!謝謝!