Q. f(n)=2⋅(−3)nComplete the recursive formula of f(n).f(1)=□f(n)=f(n−1)⋅□
Given Explicit Formula: We are given the explicit formula for the sequence: f(n)=2×(−3)n. To find the recursive formula, we need to express f(n) in terms of f(n−1).
Find f(1): First, let's find f(1) by substituting n=1 into the explicit formula.f(1)=2×(−3)1=2×(−3)=−6.So, f(1)=−6.
Relationship between f(n) and f(n−1): Now, let's find the relationship between f(n) and f(n−1). We know that f(n)=2×(−3)n and f(n−1)=2×(−3)n−1.
Divide f(n) by f(n−1): To find f(n) in terms of f(n−1), we can divide f(n) by f(n−1):f(n−1)f(n)=2⋅(−3)n−12⋅(−3)n.
Simplify the Expression: Simplify the expression by canceling out common factors and using the properties of exponents: f(n−1)f(n)=(−3)n−1(−3)n=(−3)n−(n−1)=(−3)1=−3.
Express f(n) in terms of f(n−1): Now we can express f(n) in terms of f(n−1):f(n)=−3×f(n−1).
Combine Initial Condition: Combine the initial condition f(1)=−6 with the recursive relationship we just found: f(n)=−3×f(n−1), for n > 1.
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