Q. {f(1)=−71,f(n)=f(n−1)×4.2 Find an explicit formula for f(n).f(n)=
Given information: We are given that f(1)=−71 and that f(n) is 4.2 times f(n−1). To find an explicit formula for f(n), we need to express f(n) in terms of n without the recursion.
Identifying sequence type: Since f(n)=f(n−1)×4.2, we can see that each term is 4.2 times the previous term. This is a geometric sequence with the first term f(1)=−71 and the common ratio r=4.2.
Geometric sequence formula: The explicit formula for the nth term of a geometric sequence is given by f(n)=a⋅r(n−1), where a is the first term and r is the common ratio.
Substitute values: Substitute a=−71 and r=4.2 into the formula to get f(n)=−71×4.2(n−1).
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