Q. If f(1)=8 and f(n)=−5f(n−1)−n then find the value of f(3).Answer:
Find f(2): To find f(3), we need to first find f(2) using the recursive formula f(n)=−5f(n−1)−n, with n=2 and the known value f(1)=8. f(2)=−5f(1)−2 f(2)=−5(8)−2 f(2)=−40−2 f(2)=−42
Find f(3): Now that we have f(2), we can find f(3) using the same recursive formula with n=3. f(3)=−5f(2)−3 f(3)=−5(−42)−3 f(3)=210−3 f(3)=207