Q. {f(1)=72f(n)=f(n−1)+9Find an explicit formula for f(n).f(n)=
Identify Sequence Type: Identify the type of sequence described by the function f(n). The function f(n)=f(n−1)+9 suggests that this is an arithmetic sequence because there is a constant difference between consecutive terms.
Determine First Term: Determine the first term of the sequence. We are given that f(1)=72, which means the first term, a1, is 72.
Find Common Difference: Determine the common difference of the sequence. The function f(n)=f(n−1)+9 indicates that the common difference, d, is 9 because each term is 9 more than the previous term.
Use Explicit Formula: Use the explicit formula for an arithmetic sequence, which is an=a1+(n−1)d. Substitute the values of a1 and d into the formula. In this case, a1=72 and d=9.
Write Formula: Write the explicit formula for the sequence using the values from Step 2 and Step 3. The formula is f(n)=72+(n−1)×9.
Simplify Formula: Simplify the formula. Multiply 9 by (n−1) to get 9n−9. Add this to the first term, 72, to get f(n)=72+9n−9.
Combine Like Terms: Combine like terms to get the final explicit formula. f(n)=9n+72−9 simplifies to f(n)=9n+63.
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