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{f(1)=37f(n)=f(n1)0.3\begin{cases} f(1)=37 \\\\ f(n)=f(n-1)\cdot 0.3 \end{cases} \newlineFind an explicit formula for f(n).

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Q. {f(1)=37f(n)=f(n1)0.3\begin{cases} f(1)=37 \\\\ f(n)=f(n-1)\cdot 0.3 \end{cases} \newlineFind an explicit formula for f(n).
  1. Given initial condition: We are given the initial condition f(1)=37f(1) = 37 and the recursive formula f(n)=f(n1)×0.3f(n) = f(n-1) \times 0.3. To find an explicit formula, we need to express f(n)f(n) in terms of nn without the recursion.
  2. Identify pattern in terms: Let's look at the first few terms to identify a pattern:\newlinef(1)=37f(1) = 37\newlinef(2)=f(1)×0.3=37×0.3f(2) = f(1) \times 0.3 = 37 \times 0.3\newlinef(3)=f(2)×0.3=(37×0.3)×0.3=37×0.32f(3) = f(2) \times 0.3 = (37 \times 0.3) \times 0.3 = 37 \times 0.3^2\newlineWe can see that with each step, we multiply by an additional factor of 0.30.3.
  3. Generalize formula based on pattern: Based on the pattern, we can generalize that f(n)=37×0.3(n1)f(n) = 37 \times 0.3^{(n-1)}, where nn is the term number.
  4. Verify formula for n=1n=1: To verify this formula, we can check it for n=1n=1:f(1)=37×0.3(11)=37×0.30=37×1=37f(1) = 37 \times 0.3^{(1-1)} = 37 \times 0.3^0 = 37 \times 1 = 37, which matches the given initial condition.
  5. Verify formula for n=2n=2: Now, let's check it for another value, say n=2n=2:f(2)=37×0.3(21)=37×0.31=37×0.3=11.1f(2) = 37 \times 0.3^{(2-1)} = 37 \times 0.3^1 = 37 \times 0.3 = 11.1, which matches the recursive definition f(2)=f(1)×0.3f(2) = f(1) \times 0.3.

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