Use the initial term and the recursive formula to find an explicit formula for the sequence an. Write your answer in simplest form.a1=−1an=an−1+7an=_____
Q. Use the initial term and the recursive formula to find an explicit formula for the sequence an. Write your answer in simplest form.a1=−1an=an−1+7an=_____
Initial Term and Recursive Formula: The initial term is a1=−1. The recursive formula is an=an−1+7. To find the explicit formula, we need to express an in terms of n.
Pattern of Terms: Let's look at the first few terms to see the pattern. a1=−1, a2=a1+7=−1+7=6, a3=a2+7=6+7=13, and so on.
Arithmetic Sequence: We notice that each term is 7 more than the previous term, which means the sequence is arithmetic with a common difference of 7.
Explicit Formula: The explicit formula for an arithmetic sequence is an=a1+(n−1)d, where d is the common difference. Here, a1=−1 and d=7.
Substitute Values: Substitute the values into the formula: an=−1+(n−1)×7.
Simplify Formula: Simplify the formula: an=−1+7n−7.
Combine Like Terms: Combine like terms: an=7n−8.
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