Question

[Thân Nhật Minh]

1+(1+2)+(1+2+3)+(1+2+3+4)+......+(1+2+3+4+5+......+100)​

100x1+99x2+98x3+......+2x99+1x100

Giải chi tiết giùm mình nha

Answer 1

[Nguyễn Anh Kim Hân]

\(=\frac{1+\left(1+2\right)+\left(1+2+3\right)+...+\left(1+2+3+...+100\right)}{100.1+99.2+98.3+...+2.99+1.100}\)

\(=\frac{1.100+2.99+3.98+...+99.2+100.1}{100.1+99.2+98.3+...+2.99+1.100}\)

\(=1\)