Tính tỉ số A/B biết: biểu thức A = 1/2 + 1/3 + ... + 1/2023+ 1/2024 và biểu thức B = 2023/1+2022/2+ 2021/3+ ... + 2/2022 + 1/2023
Giải thích
Ta có:
\(B = \frac{{2023}}{1} + \frac{{2022}}{2} + \frac{{2021}}{3} + ... + \frac{2}{{2022}} + \frac{1}{{2023}}\)
\(B = 1 + \left( {\frac{{2022}}{2} + 1} \right) + \left( {\frac{{2021}}{3} + 1} \right) + ... + \left( {\frac{1}{{2022}} + 1} \right) + \left( {\frac{1}{{2023}} + 1} \right)\)
\(B = 1 + \frac{{2024}}{2} + \frac{{2024}}{3} + ... + \frac{{2024}}{{2023}}\)
\(B = \frac{{2024}}{2} + \frac{{2024}}{3} + ... + \frac{{2024}}{{2023}} + 1\)
\(B = \frac{{2024}}{2} + \frac{{2024}}{3} + ... + \frac{{2024}}{{2023}} + \frac{{2024}}{{2024}}\)
\(B = 2024.\left( {\frac{1}{2} + \frac{1}{3} + ... + \frac{1}{{2023}} + \frac{1}{{2024}}} \right)\)
\(B = 2024A\)
Suy ra, \(\frac{A}{B} = \frac{1}{{2024}}\).