Công thức tổng chuổi số Pascal: Difference between revisions

Latest revision as of 02:07, 5 July 2020

$(x + y)^{n} = \sum_{r = 0}^{n} (\binom{n}{r}) x^{r} y^{n - r}$

(x + y)^{n} = (\binom{n}{0}) x^{0} y^{n} + (\binom{n}{1}) x^{1} y^{n - 1} + (\binom{n}{2}) x^{2} y^{n - 2} + \dots + (\binom{n}{n - 2}) x^{n - 2} y^{2} + (\binom{n}{n - 1}) x^{n - 1} y^{1} + (\binom{n}{n}) x^{n} y^{0}

(x + y)^{n} = y^{n} + n x y^{n - 1} + (\binom{n}{2}) x^{2} y^{n - 2} + \dots + (\binom{n}{n - 2}) x^{n - 2} y^{2} + n x^{n - 1} y + x^{n}

Với

(\binom{n}{r}) = \frac{n!}{r! (n - r)!}

Thi du