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Which recursive formula can be used to define this sequence for n>1n > 1?\newline5,18,31,44,57,70,5, 18, 31, 44, 57, 70, \ldots\newlineChoices:\newline(A)an=an1+an213a_n = a_{n-1} + a_{n-2} - 13\newline(B)an=an1+13a_n = a_{n-1} + 13\newline(C)an=an113a_n = a_{n-1} - 13\newline(D)an=185an1a_n = \frac{18}{5}a_{n-1}

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Q. Which recursive formula can be used to define this sequence for n>1n > 1?\newline5,18,31,44,57,70,5, 18, 31, 44, 57, 70, \ldots\newlineChoices:\newline(A)an=an1+an213a_n = a_{n-1} + a_{n-2} - 13\newline(B)an=an1+13a_n = a_{n-1} + 13\newline(C)an=an113a_n = a_{n-1} - 13\newline(D)an=185an1a_n = \frac{18}{5}a_{n-1}
  1. Analyze Sequence: Analyze the sequence to determine if it is arithmetic or geometric.\newlineThe sequence is 5,18,31,44,57,70,5, 18, 31, 44, 57, 70, \ldots. To determine if it is arithmetic or geometric, we can look at the differences or ratios between terms. Let's calculate the difference between the first two terms: 185=1318 - 5 = 13. Now, let's check the difference between the second and third terms: 3118=1331 - 18 = 13. Since the difference is consistent, we can conclude that the sequence is arithmetic with a common difference of 1313.
  2. Identify Recursive Formula: Identify the recursive formula for the given arithmetic sequence.\newlineSince we have determined that the sequence is arithmetic with a common difference of 1313, the recursive formula will involve adding 1313 to the previous term to get the next term. Therefore, the recursive formula will be of the form an=an1+da_n = a_{n-1} + d, where dd is the common difference.
  3. Substitute Common Difference: Substitute the common difference into the recursive formula.\newlineWe have found that the common difference dd is 1313. Substituting this into the recursive formula gives us an=a(n1)+13a_n = a_{(n-1)} + 13.
  4. Match Recursive Formula: Match the correct recursive formula with the given choices.\newlineThe recursive formula we have found is an=an1+13a_n = a_{n-1} + 13. Now, let's look at the choices provided:\newline(A) a=a+a13a = a + a - 13 (This is not a valid recursive formula; it doesn't make sense mathematically.)\newline(B) a=a+13a = a + 13 (This choice is missing the subscript nn and (n1)(n-1) to denote the terms in the sequence.)\newline(C) a=a13a = a - 13 (This would imply the sequence is decreasing by 1313, which is not the case.)\newline(D) a=185aa = \frac{18}{5}a (This implies a geometric sequence with a ratio of 185\frac{18}{5}, which is not correct.)\newlineThe correct choice that matches our recursive formula is not listed exactly as we have it, but choice (B) is the closest if we correct it to include the proper subscripts: an=an1+13a_n = a_{n-1} + 13.

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