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Write an explicit formula that represents the sequence defined by the following recursive formula:

a_(1)=8" and "a_(n)=a_(n-1)-2
Answer: 
a_(n)=

Write an explicit formula that represents the sequence defined by the following recursive formula:\newlinea1=8 and an=an12 a_{1}=8 \text { and } a_{n}=a_{n-1}-2 \newlineAnswer: an= a_{n}=

Full solution

Q. Write an explicit formula that represents the sequence defined by the following recursive formula:\newlinea1=8 and an=an12 a_{1}=8 \text { and } a_{n}=a_{n-1}-2 \newlineAnswer: an= a_{n}=
  1. Identify Pattern: To find the explicit formula for the given recursive sequence, we need to determine a pattern that relates the term number nn directly to its value without relying on the previous term.
  2. Write Out Terms: Let's start by writing out the first few terms of the sequence using the recursive formula:\newlinea1=8a_{1} = 8 (given)\newlinea2=a12=82=6a_{2} = a_{1} - 2 = 8 - 2 = 6\newlinea3=a22=62=4a_{3} = a_{2} - 2 = 6 - 2 = 4\newlinea4=a32=42=2a_{4} = a_{3} - 2 = 4 - 2 = 2\newlineFrom this pattern, we can see that each term is 22 less than the previous term.
  3. Determine Relationship: Now, let's find the relationship between the term number nn and the term value. We can see that:\newlinea1=8=82(11)a_{1} = 8 = 8 - 2(1 - 1)\newlinea2=6=82(21)a_{2} = 6 = 8 - 2(2 - 1)\newlinea3=4=82(31)a_{3} = 4 = 8 - 2(3 - 1)\newlinea4=2=82(41)a_{4} = 2 = 8 - 2(4 - 1)\newlineIt seems that the term value is equal to 88 minus 22 times (n1)(n - 1).
  4. Generalize Formula: To confirm the pattern, let's generalize the formula:\newlinean=82(n1)a_{n} = 8 - 2(n - 1)\newlineSimplifying the formula, we get:\newlinean=82n+2a_{n} = 8 - 2n + 2\newlinean=102na_{n} = 10 - 2n\newlineThis is the explicit formula for the given sequence.

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