Challenging!
2007-07-09 9:28 pm
The coefficient of a^(r-1), a^r and a^(r+1) in the expansion of (1+a)^n are in A.P., prove that n^2 - n(4r+1) + (4r^2-2) = 0.
回答 (1)
2007-07-09 9:52 pm
參考: My Maths knowledge
收錄日期: 2021-04-23 17:12:36
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