Question

[Nkoc Nki Nko]

\(y=\frac{999}{1000}+\frac{998}{1000}+\frac{997}{1000}+...+\frac{1}{1000}\)

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Answer 1

[Tôi thích hoa hồng]

\(y=\frac{999}{1000}+\frac{998}{1000}+\frac{997}{1000}+...+\frac{1}{1000}\)với 999 phân số

\(\Rightarrow y=\left(\frac{999}{1000}+\frac{1}{1000}\right)+\left(\frac{998}{1000}+\frac{2}{1000}\right)+...+\left(\frac{501}{1000}+\frac{499}{1000}\right)+\frac{500}{1000}\)

                                                               có 49 cặp                                               

\(\Rightarrow y=1+1+1+...+1+\frac{1}{2}\)với 49 số 1

\(\Rightarrow y=49+\frac{1}{2}=49\frac{1}{2}\)

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Answer 2

[Zeref Dragneel]

\(y=\frac{999}{1000}+\frac{998}{1000}+\frac{997}{1000}+...+\frac{1}{1000}\)

\(y=\frac{999+998+997+...+1}{1000}\)

\(y=\frac{999\left(999+1\right):2}{1000}\)

\(y=\frac{499500}{1000}=499,5\)