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Let f(n) denote the n^(th) terms of the ...

Let `f(n)` denote the `n^(th)` terms of the seqence of `3,6,11,18,27,….` and `g(n)` denote the `n^(th)` terms of the seqence of `3,7,13,21,….` Let `F(n)` and `G(n)` denote the sum of `n` terms of the above sequences, respectively. Now answer the following:
`lim_(ntooo)(F(n))/(G(n))=`

A

`2`

B

`1`

C

`0`

D

`oo`

Text Solution

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The correct Answer is:
To solve the problem, we need to find the limit of the ratio of the sums of the terms of two sequences as \( n \) approaches infinity. Let's break down the solution step by step. ### Step 1: Identify the nth terms of the sequences The first sequence is \( 3, 6, 11, 18, 27, \ldots \). We can observe the pattern in the differences: - \( 6 - 3 = 3 \) - \( 11 - 6 = 5 \) - \( 18 - 11 = 7 \) - \( 27 - 18 = 9 \) The differences are \( 3, 5, 7, 9, \ldots \), which is an arithmetic sequence with a common difference of \( 2 \). Thus, the \( n^{th} \) term \( f(n) \) can be expressed as: \[ f(n) = n^2 + 2 \] ### Step 2: Find the sum of the first n terms \( F(n) \) The sum of the first \( n \) terms \( F(n) \) is given by: \[ F(n) = \sum_{k=1}^{n} f(k) = \sum_{k=1}^{n} (k^2 + 2) \] Using the formula for the sum of squares and the sum of a constant: \[ F(n) = \frac{n(n+1)(2n+1)}{6} + 2n \] ### Step 3: Identify the nth terms of the second sequence The second sequence is \( 3, 7, 13, 21, \ldots \). The differences are: - \( 7 - 3 = 4 \) - \( 13 - 7 = 6 \) - \( 21 - 13 = 8 \) The differences are \( 4, 6, 8, \ldots \), which is also an arithmetic sequence with a common difference of \( 2 \). Thus, the \( n^{th} \) term \( g(n) \) can be expressed as: \[ g(n) = n^2 + n + 1 \] ### Step 4: Find the sum of the first n terms \( G(n) \) The sum of the first \( n \) terms \( G(n) \) is given by: \[ G(n) = \sum_{k=1}^{n} g(k) = \sum_{k=1}^{n} (k^2 + k + 1) \] Using the formulas for the sum of squares, the sum of the first \( n \) natural numbers, and the sum of a constant: \[ G(n) = \frac{n(n+1)(2n+1)}{6} + \frac{n(n+1)}{2} + n \] ### Step 5: Calculate the limit Now, we need to find: \[ \lim_{n \to \infty} \frac{F(n)}{G(n)} \] Substituting the expressions for \( F(n) \) and \( G(n) \): \[ \lim_{n \to \infty} \frac{\frac{n(n+1)(2n+1)}{6} + 2n}{\frac{n(n+1)(2n+1)}{6} + \frac{n(n+1)}{2} + n} \] As \( n \) approaches infinity, the dominant terms in both the numerator and denominator are \( \frac{n^3}{3} \) and \( \frac{n^3}{3} \) respectively. Therefore, we can simplify: \[ \lim_{n \to \infty} \frac{F(n)}{G(n)} = \frac{1}{1} = 1 \] ### Final Answer Thus, the limit is: \[ \lim_{n \to \infty} \frac{F(n)}{G(n)} = 1 \]

To solve the problem, we need to find the limit of the ratio of the sums of the terms of two sequences as \( n \) approaches infinity. Let's break down the solution step by step. ### Step 1: Identify the nth terms of the sequences The first sequence is \( 3, 6, 11, 18, 27, \ldots \). We can observe the pattern in the differences: - \( 6 - 3 = 3 \) - \( 11 - 6 = 5 \) ...
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