Q. Write an explicit formula for an, the nth term of the sequence 72,−24,8,…Answer: an=
Determine Pattern: To find the explicit formula for the nth term of the sequence, we first need to determine the pattern of the sequence. We can do this by examining the relationship between consecutive terms.
Identify Geometric Sequence: The second term is −24, which is −31 of the first term 72. The third term is 8, which is −31 of the second term −24. This suggests that each term is −31 times the previous term, indicating that the sequence is geometric.
Use Geometric Sequence Formula: For a geometric sequence, the nth term is given by the formula an=a1×r(n−1), where a1 is the first term and r is the common ratio. In this sequence, a1=72 and r=−31.
Write Explicit Formula: Now we can write the explicit formula for the nth term of the sequence using the values of a1 and r. The formula is an=72×(−31)(n−1).
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