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Evaluate n=12+n12n\sum_{n=1}^{\infty}\frac{2+n}{1-2n}

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Q. Evaluate n=12+n12n\sum_{n=1}^{\infty}\frac{2+n}{1-2n}
  1. Identify Series Form: The given series is an infinite series of the form n=12+n12n\sum_{n=1}^{\infty}\frac{2+n}{1-2n}. To evaluate this, we need to determine if the series converges and, if so, find its sum. We can start by looking for a pattern or a formula that represents the general term of the series.
  2. General Term Calculation: The general term of the series is an=2+n12na_n = \frac{2+n}{1-2n}. To check for convergence, we can use the nth-term test for divergence, which states that if the limit of ana_n as nn approaches infinity is not zero, then the series diverges.
  3. Convergence Test: Let's calculate the limit of ana_n as nn approaches infinity:\newlinelimn2+n12n=limn2n+11n2.\lim_{n\to\infty}\frac{2+n}{1-2n} = \lim_{n\to\infty}\frac{\frac{2}{n} + 1}{\frac{1}{n} - 2}.\newlineAs nn approaches infinity, the terms 2n\frac{2}{n} and 1n\frac{1}{n} approach 00, so the limit simplifies to:\newlinelimn0+102=12.\lim_{n\to\infty}\frac{0 + 1}{0 - 2} = -\frac{1}{2}.
  4. Limit Calculation: Since the limit of the general term ana_n as nn approaches infinity is 12-\frac{1}{2}, which is not equal to zero, the nth-term test for divergence tells us that the series does not converge. Therefore, the sum of the series is not a finite number.

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