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1 + (3)/(1!) + (5)/(2!) + (7)/(3!) + (9)...

`1 + (3)/(1!) + (5)/(2!) + (7)/(3!) + (9)/(4!) + ... = `..........

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To solve the series \( S = 1 + \frac{3}{1!} + \frac{5}{2!} + \frac{7}{3!} + \frac{9}{4!} + \ldots \), we can follow these steps: ### Step 1: Identify the General Term The series can be expressed in terms of a general term. Observing the pattern, we can see that the \( n \)-th term can be written as: \[ \text{Term}_n = \frac{(2n + 1)}{n!} \] where \( n \) starts from 0. ### Step 2: Rewrite the Series Thus, we can rewrite the series as: \[ S = \sum_{n=0}^{\infty} \frac{(2n + 1)}{n!} \] ### Step 3: Split the Series We can split the series into two parts: \[ S = \sum_{n=0}^{\infty} \frac{2n}{n!} + \sum_{n=0}^{\infty} \frac{1}{n!} \] The first part can be simplified as follows: \[ \sum_{n=0}^{\infty} \frac{2n}{n!} = 2 \sum_{n=1}^{\infty} \frac{1}{(n-1)!} = 2 \sum_{m=0}^{\infty} \frac{1}{m!} = 2e \] where we made the substitution \( m = n - 1 \). ### Step 4: Evaluate the Second Part The second part is: \[ \sum_{n=0}^{\infty} \frac{1}{n!} = e \] ### Step 5: Combine the Results Now, we combine both parts: \[ S = 2e + e = 3e \] ### Final Answer Thus, the sum of the series is: \[ S = 3e \] ---
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