Given a series whose first element is 1.5.
Each element of the series is greater by 3 of its predecessor.
Is the number 29 an element in the series?
If so, please indicate your place in the series.
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Given a series whose first element is 1.5.
Each element of the series is greater by 3 of its predecessor.
Is the number 29 an element in the series?
If so, please indicate your place in the series.
To determine whether the number 29 is an element of the series, we start by recognizing that the problem involves an arithmetic sequence. In such a sequence, each term is generated by adding a constant difference to the previous term. Here, the first term is , and the common difference is .
The formula for the nth term of an arithmetic sequence is given by:
We need to check if 29 is one of the terms of this series, so we set and solve for :
Subtract 1.5 from both sides:
Divide both sides by 3 to solve for :
Add 1 to find :
Since is not an integer, the number 29 does not appear as an element in this sequence. Arithmetic sequences only have integer positions for their terms, so must be a whole number for 29 to be a term. As a result, the correct answer is:
No
No
Is there a term-to-term rule for the sequence below?
18 , 22 , 26 , 30
When you solve for n and get a decimal like 10.167, it means the target number falls between two consecutive terms in the sequence. Since sequence positions must be whole numbers, the target is not in the sequence.
Calculate the 10th and 11th terms! The 10th term: and 11th term: . So 29 falls between these values.
Think about it logically: you can have the 1st term, 2nd term, 3rd term, etc. But what would the 2.5th term mean? Sequence positions represent counting numbers, which are always whole numbers.
The same process applies! Always substitute into and solve for n. If n is a positive integer, the number is in the sequence. If not, it isn't!
Absolutely! This algebraic approach works for any arithmetic sequence. Just identify (first term) and (common difference), then solve for your target value.
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