: 1 1 1
: GF: ------ * ---------- * ... * -------
: 1-nX 1-(n-1)X 1-X
: --
: ※ 發信站: 批踢踢實業坊(ptt.cc)
: ◆ From: 59.126.187.85
: ※ 編輯: privatewind 來自: 59.126.187.85 (09/30 17:13)
: ※ 編輯: privatewind 來自: 59.126.187.85 (09/30 17:15)
: → a016258:你可以show 一下 n=2,m=3 跟 n=3,m=6 只有一組解嗎? 09/30 18:23
n=2, m=3
1 1 infinite infinite
GF: ------ * ------ = sum ( sum (2X)^a * (X)b )
1-2X 1-X a=0 b=0
a+b = m - (n+1)*n/2 = 3 - 3*2/2 =0
[X^0] = 1
=====================================================================
n=3, m=6
1 1 1 inf inf inf
GF: ------ * ------ * ------ = sum ( sum ( sum (3X)^a * (2X)^b * (X)^c
1-3X 1-2X 1-X a=0 b=0 c=0
a+b+c = m - (n+1)*n/2 = 6 - 4*3/2 =0
[X^0] =1
--
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