作者jjx66os (igor)
看板trans_math
标题[多变] 再一题二元变数极值
时间Sat Jun 2 23:32:08 2012
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=?????
请问这该怎麽解呢?
谢谢~
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◆ From: 61.225.197.186
1F：推 suhorng:Gx=0:x(3x-2)+3y(3x-2)=0→(x+3y)(3x-2)=0 61.217.34.17 06/02 23:57
2F：→ suhorng:1.x=2/3代到Gy=0求y 2.x=-3y代到Gy=0求x,y 61.217.34.17 06/02 23:58
3F：→ jjx66os:噢噢了解!太感谢你了，帮我解了两题!谢谢! 61.225.197.186 06/03 00:17