How do we guess some equations like
1^2 + 2^2 + 3^2 + ... + n^2 is equal to [n(n + 1)(2n + 1)]/6
and
1 x 3 + 3 x 5 + 5 x 7 + ... + (2n - 1)(2n + 1) is equal to [(2n - 1)(2n + 1)(2n + 3) + 3]/6
before we prove it? Is it by trial and error?
收錄日期: 2021-05-01 13:03:17
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20101006065734AARUmTi