Q. Write an explicit formula for an, the nth term of the sequence 24,−12,6,…Answer: an=
Identify Sequence Type: Identify whether the given sequence is geometric or arithmetic. The sequence 24,−12,6,… has a common ratio between consecutive terms, as each term is obtained by multiplying the previous term by a constant. To find this constant, we can divide the second term by the first term: −12/24=−1/2. Similarly, dividing the third term by the second term gives 6/−12=−1/2. Since the ratio is consistent, the sequence is geometric.
Use Explicit Formula: Use the explicit formula for a geometric sequence, an=a1×r(n−1), where a1 is the first term and r is the common ratio. For the sequence 24,−12,6,…, the first term, a1, is 24 and the common ratio, r, is −21.
Substitute Values: Substitute the values of a1 and r into the formula to write an expression to describe the sequence. The expression for the sequence 24,−12,6,extellipsis is a_n = 24 imes (-rac{1}{2})^{(n-1)}.
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