Q. Complete the recursive formula of the arithmetic sequence−1,−13,−25,−37,….a(1)=□a(n)=a(n−1)+□
Identify first term: Identify the first term of the sequence. The first term of the sequence is given as −1. This will be our a(1) in the recursive formula.
Determine common difference: Determine the common difference between consecutive terms. To find the common difference, subtract the first term from the second term: −13−(−1)=−12. This is the common difference d for the arithmetic sequence.
Write recursive formula: Write the recursive formula using the first term and the common difference. The recursive formula for an arithmetic sequence is a(n)=a(n−1)+d. Since we have a(1)=−1 and d=−12, the recursive formula becomes a(n)=a(n−1)−12.
Check formula with given terms: Check the recursive formula with the given terms to ensure it is correct. If we apply the formula a(n)=a(n−1)−12 starting from the first term, we should get the subsequent terms of the sequence. For example, a(2) should be a(1)−12, which is −1−12=−13. This matches the second term of the sequence, so the formula appears to be correct.
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