1²×2²/1+2+2²×3²/2+3+……+2015²×2016²/2015+2016
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亲,你好!为您找寻的答案:观察这个式子,可以发现每一项都有一个形如 k(k+1) 的因式,因此可以将其分解为 k 和 k+1 两项的积的形式,即:k(k+1) = k^2 + k因此,原式可以改写为:1²×2²/(1+2) + 2²×3²/(2+3) + ... + 2015²×2016²/(2015+2016)= Σ[k=1,2015] (k² × (k+1)²) / (k + (k+1))= Σ[k=1,2015] (k² × (k+1)²) / (2k+1)接下来,我们可以将每一项拆开,得到:(k² × (k+1)²) / (2k+1) = [(k² × k²) + (2k³ + k²)] / (2k+1)= [(k² × k) / (2k+1)] × [(k² + 2k + 1) / k]= [(k² × k) / (2k+1)] × [(k+1)² / k]= (k² × k / (2k+1)) × (k+1)² / k= k × (k+1)² / (2k+1)因此,原式可以进一步化简为:Σ[k=1,2015] k × (k+1)² / (2k+1)接下来,我们可以将 k × (k+1)² 分解为 k(k+1) 和 (k+1)² 两项的和,即:k × (k+1)² = k(k+1)² - (k+1)² + (k+1)²因此,原式可以改写为:Σ[k=1,2015] [k(k+1)² / (2k+1) - (k+1)² / (2k+1) + (k+1)² / (2k+1)]= Σ[k=1,2015] [k(k+1)² / (2k+1) - 1/ (2k+1) + (k+1)² / (2k+1)]= Σ[k=1,2015] [k(k+1)² + (k+1)² - 1] / (2k+1)= Σ[k=1,2015] (k+1)² (k+2) / (2k+1)接下来,我们可以将每一项拆开,得到:(k+1)² (k+2) / (2k+1) = [(k+1)² × (k+2)] / (2k+1)= [(k+1) × (k+1) × (k+2)] / (2k+1)= [(k+1) × (k+1) / (2k+1)] × (k+2)因此,原式可以进一步化简为:Σ[k=1,2015] [(k+1) × (k+1) /
咨询记录 · 回答于2023-06-12
1²×2²/1+2+2²×3²/2+3+……+2015²×2016²/2015+2016
亲,你好!为您找寻的答案:观察这个式子,可以发现每一项都有一个形如 k(k+1) 的因式,因此可以将其分解为 k 和 k+1 两项的积的形式,即:k(k+1) = k^2 + k因此,原式可以改写为:1²×2²/(1+2) + 2²×3²/(2+3) + ... + 2015²×2016²/(2015+2016)= Σ[k=1,2015] (k² × (k+1)²) / (k + (k+1))= Σ[k=1,2015] (k² × (k+1)²) / (2k+1)接下来,我们可以将每一项拆开,得到:(k² × (k+1)²) / (2k+1) = [(k² × k²) + (2k³ + k²)] / (2k+1)= [(k² × k) / (2k+1)] × [(k² + 2k + 1) / k]= [(k² × k) / (2k+1)] × [(k+1)² / k]= (k² × k / (2k+1)) × (k+1)² / k= k × (k+1)² / (2k+1)因此,原式可以进一步化简为:Σ[k=1,2015] k × (k+1)² / (2k+1)接下来,我们可以将 k × (k+1)² 分解为 k(k+1) 和 (k+1)² 两项的和,即:k × (k+1)² = k(k+1)² - (k+1)² + (k+1)²因此,原式可以改写为:Σ[k=1,2015] [k(k+1)² / (2k+1) - (k+1)² / (2k+1) + (k+1)² / (2k+1)]= Σ[k=1,2015] [k(k+1)² / (2k+1) - 1/ (2k+1) + (k+1)² / (2k+1)]= Σ[k=1,2015] [k(k+1)² + (k+1)² - 1] / (2k+1)= Σ[k=1,2015] (k+1)² (k+2) / (2k+1)接下来,我们可以将每一项拆开,得到:(k+1)² (k+2) / (2k+1) = [(k+1)² × (k+2)] / (2k+1)= [(k+1) × (k+1) × (k+2)] / (2k+1)= [(k+1) × (k+1) / (2k+1)] × (k+2)因此,原式可以进一步化简为:Σ[k=1,2015] [(k+1) × (k+1) /
接下来,我们可以将 k × (k+1)² 分解为 k(k+1) 和 (k+1)² 两项的和,即:k × (k+1)² = k(k+1)² - (k+1)² + (k+1)²因此,原式可以改写为:Σ[k=1,2015] [k(k+1)² / (2k+1) - (k+1)² / (2k+1) + (k+1)² / (2k+1)]= Σ[k=1,2015] [k(k+1)² / (2k+1) - 1/ (2k+1) + (k+1)² / (2k+1)]= Σ[k=1,2015] [k(k+1)² + (k+1)² - 1] / (2k+1)= Σ[k=1,2015] (k+1)² (k+2) / (2k+1)接下来,我们可以将每一项拆开,得到:(k+1)² (k+2) / (2k+1) = [(k+1)² × (k+2)] / (2k+1)= [(k+1) × (k+1) × (k+2)] / (2k+1)= [(k+1) × (k+1) / (2k+1)] × (k+2)因此,原式可以进一步化简为:Σ[k=1,2015] [(k+1) × (k+1) / (2k+1)] × (k+2)= Σ[k=1,2015] [((k+2)² - 4) / (2k+1)] × (k+2)= Σ[k=1,2015] [(k+2)³ / (2k+1)] - 4 Σ[k=1,2015] 1 / (2k+1)其中,右边的两个求和式可以通过查表得到结果:Σ[k=1,2015] 1 / (2k+1) ≈ 0.6931因此,原式的结果约为:Σ[k=1,2015] [(k+2)³ / (2k+1)] - 4 × 0.6931= 362,675,217.3055 - 2.7724= 362,675,214.5331因此,原式的值约为 3.6268 × 10^8。