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A certain sequence is defined by the formula an = an – 1 – 7
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30 Jul 2018, 10:28
30 Jul 2018, 10:28
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Expert Reply
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Question Stats:
47% (01:19) correct
52% (01:26) wrong based on 94 sessions
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A certain sequence is defined by the formula \(a_n = a_{n – 1} – 7\).
\(a_7 = 7\)
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
\(a_7 = 7\)
Quantity A |
Quantity B |
\(a_1\) |
\(-35\) |
A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.
Re: A certain sequence is defined by the formula an = an – 1 – 7
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12 Aug 2018, 05:41
12 Aug 2018, 05:41
1
Expert Reply
Explanation
The sequence \(a_n = a_{n - 1} - 7\) can be read as “to get any term in sequence a, subtract 7 from the previous term.” The problem provides the 7th term; plug the term into the function in order to determine the pattern.
Note that Quantity A asks for the value of a1, so try to find the 6th term:
\(7 = a_6 - 7\)
\(a_6 = 14\)
In other words, each previous term will be 7 greater than the subsequent term. Therefore, \(a_7 = 7\), \(a_6 = 14\), \(a_5 = 21\), and so on.
The term \(a_1\), then, is greater than the starting point, 7, and must also be greater than the negative value in Quantity B. Quantity A is greater. Note that the value in Quantity B is the result of incorrectly subtracting 7 six times, rather than adding it.
The sequence \(a_n = a_{n - 1} - 7\) can be read as “to get any term in sequence a, subtract 7 from the previous term.” The problem provides the 7th term; plug the term into the function in order to determine the pattern.
Note that Quantity A asks for the value of a1, so try to find the 6th term:
\(7 = a_6 - 7\)
\(a_6 = 14\)
In other words, each previous term will be 7 greater than the subsequent term. Therefore, \(a_7 = 7\), \(a_6 = 14\), \(a_5 = 21\), and so on.
The term \(a_1\), then, is greater than the starting point, 7, and must also be greater than the negative value in Quantity B. Quantity A is greater. Note that the value in Quantity B is the result of incorrectly subtracting 7 six times, rather than adding it.
Re: A certain sequence is defined by the formula an = an – 1 – 7
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25 Oct 2018, 04:37
25 Oct 2018, 04:37
I didnt get it
