Question

tính nhanh:    1- 1/2 - 1/4 - 1/8 - 1/16

Answer 1

\(1-\frac{1}{2}-\frac{1}{4}-\frac{1}{8}-\frac{1}{16}=1-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=1-\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{8}+\frac{1}{8}-\frac{1}{16}\right)\)

\(=1-\left(1-\frac{1}{16}\right)=1-1+\frac{1}{16}=0+\frac{1}{16}=\frac{1}{16}\)

Answer 2

cám ơn nhìu lắm Nguyen Thieu Cong Thanh

Answer 3

Đặt 1 - 1/2 - 1/4 - 1/8 - 1/16 =A

(Nhân cả 2 vế với 2 ta có)

A = 2- (1- 1/2 -1/4 -1/8)

A=2 - a

A =2