1+1/2+1/3+...+1/2011 +1/2012 A=---------------------------------------------- 2013/1 +2014/2+...4024/2012-2012
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18 Tham khảo câu trả lời từ Trợ lý ảo Lazi To simplify the expression \[ A = \frac{1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{2011} + \frac{1}{2012}}{\frac{2013}{1} + \frac{2014}{2} + \ldots + \frac{4024}{2012} - 2012}, \] we first analyze the numerator and the denominator separately. ### Numerator The numerator is \[ S = 1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{2012}. \] This is the harmonic sum \( H_{2012} \). ### Denominator The denominator can be simplified as follows: \[ D = \frac{2013}{1} + \frac{2014}{2} + \ldots + \frac{4024}{2012} - 2012. \] We can express \( D \) as: \[ D = \sum_{k=1}^{2012} \frac{2012 + k}{k} - 2012. \] This can be broken into two parts: \[ D = \sum_{k=1}^{2012} \frac{2012}{k} + \sum_{k=1}^{2012} 1 - 2012, \] which simplifies to: \[ D = 2012 H_{2012} + 2012 - 2012 = 2012 H_{2012}. \] ### Final Simplification Now substituting back into our expression for \( A \): \[ A = \frac{H_{2012}}{2012 H_{2012}}. \] We simplify to: \[ A = \frac{1}{2012}. \] Thus, the final result is \[ \boxed{\frac{1}{2012}}. \]