Write an equation to describe the sequence below. Use n to represent the position of a term in the sequence, where n=1 for the first term. 6,−18,54,…Write your answer using decimals and integers.an=____(____)n−1
Q. Write an equation to describe the sequence below. Use n to represent the position of a term in the sequence, where n=1 for the first term. 6,−18,54,…Write your answer using decimals and integers.an=____(____)n−1
Identify sequence type: Identify the type of sequence.We have the sequence: 6,−18,54,…To determine if the sequence is arithmetic or geometric, we look at the relationship between consecutive terms.6 to −18 is multiplied by −3, and −18 to 54 is also multiplied by −3.Since each term is multiplied by a common ratio, the sequence is geometric.
Determine first term and ratio: Determine the first term (a1) and the common ratio (r).The first term: a1=6To find the common ratio, divide the second term by the first term: r=6−18=−3
Write nth term formula: Write the formula for the nth term of a geometric sequence.The general formula for the nth term of a geometric sequence is:an=a1×r(n−1)
Substitute values into formula: Substitute the values of a1 and r into the formula.Substitute 6 for a1 and −3 for r into the formula:an=6×(−3)n−1
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