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Chứng minh

A=1/3.4+1/4.5+...+1/50.51

Trúc Giang · Accepted Answer

$\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{50.51}$

$=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{50}-\frac{1}{51}$

$=\frac{1}{3}-\frac{1}{51}$

$=\frac{17}{51}-\frac{1}{51}$

$=\frac{16}{51}$Câu trả lời: $\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{50.51}$

$=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{50}-\frac{1}{51}$

$=\frac{1}{3}-\frac{1}{51}$

$=\frac{17}{51}-\frac{1}{51}$

$=\frac{16}{51}$