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3Â¥: Originally posted by ÍØº£1627 at 2015-01-07 18:48:27
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max(xyz-k*(xy+yz+zx))

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ÍØº£1627(feixiaolin´ú·¢): ½ð±Ò+5 2015-01-09 11:06:51
Reduce one dimension first. The problem is:
Given the circumference of a rectangle, find the biggest area of it.
The answer is square.  But there is no smallest area.

I believe for 3D, this also true. That is cube has the biggest volume given the same surface area.
Сľ³æ¸øÎÒÎÂů£¬¸øÎÒÏ£Íû£¬°®¾ÍÒª°®Ð¡Ä¾³æ¡£
6Â¥2015-01-08 11:20:36
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3Â¥: Originally posted by ÍØº£1627 at 2015-01-07 18:48:27
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xyz-k*(xy+yz+zx) >= xyz-k*pow(xy*yz*zx, 1/3)/3 = xyz-k*pow(xyz,2/3)/3
S.T.  x=y=z
7Â¥2015-01-08 16:26:56
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ÒýÓûØÌû:
6Â¥: Originally posted by zaq123321 at 2015-01-08 11:20:36
Reduce one dimension first. The problem is:
Given the circumference of a rectangle, find the biggest area of it.
The answer is square.  But there is no smallest area.

I believe for 3D, this als ...

thank  you!
8Â¥2015-01-09 15:11:53
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ÒýÓûØÌû:
7Â¥: Originally posted by feixiaolin at 2015-01-08 16:26:56
xyz-k*(xy+yz+zx) >= xyz-k*pow(xy*yz*zx, 1/3)/3 = xyz-k*pow(xyz,2/3)/3
S.T.  x=y=z...

лл
9Â¥2015-01-09 15:31:11
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½ð³æ (СÓÐÃûÆø)

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2Â¥: Originally posted by feixiaolin at 2015-01-07 16:15:38
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