
Re: 一題複數

: 如圖
: 高中數學競賽的試題
: 只能列出w^35+w^34+....+w+1=0
: 不知道怎麼轉換
: -----
: Sent from JPTT on my Samsung SM-G900I.
w^36 = 1
1 + w + w^2 + ... + w^35 = 0
S = w + 2w^2 + ... + 36w^36
wS = w^2 + ... + 35w^36 + 36w^37
(1 - w)S = w + w^2 + ... w^35 + 1 + 36w
= 36w
=> 所求 = |1 - w|/36
= (2/36)sin(5度)
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