[理工] [離散]-成大電通97-電通甲

[love5566188 (I'dont kown)]

2.
  Find the number of n-digital words renerated from the alphabet{0,1,2,3,4}
  in each of which the total number of 0's and 1's is even.

請問這樣怎麼求出來?

--
※ 發信站: 批踢踢實業坊(ptt.cc) 
◆ From: 175.98.50.200
推 ah941206:遞迴或指數生成函數吧
→ love5566188:我有想過,但一次要討論0和1就不太曉得了
推 timygt:0 1 都偶 AND 0 1 都奇
推 ah941206:我用遞迴解也是卡住
→ ah941206:用生成函數解出來是 1/4*(1+5^n+2*3^n)
推 s09759017:最後會變((e^x)^3)((e^x+e^-x)/2)^2
→ s09759017:=(e^5x + 2e^3x + e^x)/4
→ s09759017:應該?