Question

[Yến Phạm]

Tính nhanh

1/3+1/6+1/12+1/24+1/48+1/96+1/192

Answer 1

[Thắng Nguyễn]

\(=2\left(\frac{1}{3}+\frac{1}{6}+...+\frac{1}{192}\right)\)

\(=2\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{6}+...+\frac{1}{96}-\frac{1}{192}\right)\)

\(=2\left(1-\frac{1}{192}\right)\)

\(=2\times\frac{191}{192}\)

\(=\frac{191}{96}\)