Câu hỏi của Đặng Thị Ngọc Anh

Question

Cho C = 2¹ + 2³ + 2⁵+ ............... +2¹⁰¹và D= 2^103.Tinh D - 3C

Nguyệt · Accepted Answer

$2^2C=2^2.\left(2^1+2^3+...+2^{101}\right)$

$2^2C=2^3+2^5+...+2^{103}$

$2^2C-C=2^3+2^5+...+2^{103}-\left(2^1+2^3+...+2^{101}\right)$

$3C=2^{103}-2$

$=>D-3C=2^{103}-2^{103}+2=2$

Câu trả lời:

$2^2C=2^2.\left(2^1+2^3+...+2^{101}\right)$

$2^2C=2^3+2^5+...+2^{103}$

$2^2C-C=2^3+2^5+...+2^{103}-\left(2^1+2^3+...+2^{101}\right)$

$3C=2^{103}-2$

$=>D-3C=2^{103}-2^{103}+2=2$