Q. Write an explicit formula that represents the sequence defined by the following recursive formula:a1=8 and an=an−1−2Answer: an=
Identify Pattern: To find the explicit formula for the given recursive sequence, we need to determine a pattern that relates the term number n directly to its value without relying on the previous term.
Write Out Terms: Let's start by writing out the first few terms of the sequence using the recursive formula:a1=8 (given)a2=a1−2=8−2=6a3=a2−2=6−2=4a4=a3−2=4−2=2From this pattern, we can see that each term is 2 less than the previous term.
Determine Relationship: Now, let's find the relationship between the term number n and the term value. We can see that:a1=8=8−2(1−1)a2=6=8−2(2−1)a3=4=8−2(3−1)a4=2=8−2(4−1)It seems that the term value is equal to 8 minus 2 times (n−1).
Generalize Formula: To confirm the pattern, let's generalize the formula:an=8−2(n−1)Simplifying the formula, we get:an=8−2n+2an=10−2nThis is the explicit formula for the given sequence.
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