很容易证明 y=x^x 有极值点x=1/e.

来源: michigan007 于 2011-11-03 05:40:59 [] [旧帖] [给我悄悄话] 阅读数 : (1749 bytes)

y=xx
y ' = (ln x + 1)x x

y’=0èx=1/e.  y=xx reaches the minmum at x=1/e. y’ can take any positive number x and the first derivative is negative before reches the minmum at x=1/e and positive after reaches the minmum.

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