To derive the recursive formula from the given function \( f(n) = 41 - 5n \), we need to express \( f(n) \) in terms of \( f(n-1) \).
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Calculate \( f(n - 1) \): \[ f(n - 1) = 41 - 5(n - 1) = 41 - 5n + 5 = 46 - 5n \]
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Find \( f(n) - f(n - 1) \): \[ f(n) = 41 - 5n \] Substituting \( f(n - 1) \): \[ f(n) - f(n - 1) = (41 - 5n) - (46 - 5n) = 41 - 5n - 46 + 5n = -5 \]
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Construct the recursive formula: From the previous step, we can express \( f(n) \) in terms of \( f(n - 1) \): \[ f(n) = f(n - 1) - 5 \]
Thus, the recursive formula for \( f(n) \) is:
- \( f(1) = 41 - 5(1) = 36 \)
- \( f(n) = f(n - 1) - 5 \)
So the complete recursive formula is:
- \( f(1) = 36 \)
- \( f(n) = f(n - 1) - 5 \) for \( n > 1 \)