Q. If f(1)=7 and f(n+1)=3f(n)−5 then find the value of f(5).Answer:
Understand recursive formula: Understand the recursive formula and initial condition.The recursive formula given is f(n+1)=3f(n)−5, and we know that f(1)=7. This means that to find f(5), we need to find the values of f(2), f(3), and f(4) first, using the recursive formula.
Find f(2): Find the value of f(2). Using the recursive formula, we substitute n=1 to find f(2). f(2)=3f(1)−5f(2)=3(7)−5f(2)=21−5f(2)=16
Find f(3): Find the value of f(3). Using the recursive formula, we substitute n=2 to find f(3). f(3)=3f(2)−5f(3)=3(16)−5f(3)=48−5f(3)=43
Find f(4): Find the value of f(4). Using the recursive formula, we substitute n=3 to find f(4). f(4)=3f(3)−5f(4)=3(43)−5f(4)=129−5f(4)=124
Find f(5): Find the value of f(5). Using the recursive formula, we substitute n=4 to find f(5). f(5)=3f(4)−5f(5)=3(124)−5f(5)=372−5f(5)=367
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