摘要: \(\frac{1}{m}\sum\limits_{i=1}^m(a_i-\frac{sum}{m})^2\\=\frac{1}{m}\sum\limits_{i=1}^ma_i^2+\frac{sum^2}{m^2}-2\times a_i\times\frac{sum}{m}\\=\frac{1 阅读全文
posted @ 2022-02-05 17:55 Feyn618 阅读(17) 评论(0) 推荐(0) 编辑