Câu hỏi của Nguyễn Minh Quang

Question

tinh A=1/2+1/2^2+1/2^3+.....+1/2^100

Ngô Thuỳ Yến Nhi · Accepted Answer

$A=\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{100}}$

$2A=1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{99}}$

$2A-A=1-\frac{1}{2^{100}}$

$A=1-\frac{1}{2^{100}}$

Câu trả lời:

$A=\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{100}}$

$2A=1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{99}}$

$2A-A=1-\frac{1}{2^{100}}$

$A=1-\frac{1}{2^{100}}$