Q. Write an explicit formula that represents the sequence defined by the following recursive formula:a1=75 and an=51an−1Answer: an=
Identify Pattern: The recursive formula given is an=51an−1, with the initial condition a1=75. To find an explicit formula, we need to express an in terms of n without referencing previous terms.
Calculate Terms: Let's look at the first few terms to identify a pattern. We start with a1=75. Using the recursive formula, a2=51a1=51×75. Then, a3=51a2=51×51×75, and so on.
Derive Explicit Formula: We can see that each term is (1/5) times the previous term. So, an can be written as a1×(1/5)n−1, because each step we multiply by (1/5) one more time than the previous step.
Substitute Initial Condition: Substituting the initial condition a1=75 into the pattern we found, the explicit formula becomes an=75×(51)n−1.
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