Q. If f(1)=8 and f(n)=−2f(n−1)+1 then find the value of f(5).Answer:
Given f(1)=8: We are given that f(1)=8. To find f(5), we need to find the values of f(2), f(3), f(4), and then f(5) using the recursive formula f(n)=−2f(n−1)+1.
Find f(2): First, let's find f(2) using the formula with n=2: f(2)=−2f(2−1)+1 f(2)=−2f(1)+1 f(2)=−2(8)+1 f(2)=−16+1 f(2)=−15
Find f(3): Next, we find f(3) using the formula with n=3: f(3)=−2f(3−1)+1 f(3)=−2f(2)+1 f(3)=−2(−15)+1 f(3)=30+1 f(3)=31
Find f(4): Now, we find f(4) using the formula with n=4: f(4)=−2f(4−1)+1 f(4)=−2f(3)+1 f(4)=−2(31)+1 f(4)=−62+1 f(4)=−61
Find f(5): Finally, we find f(5) using the formula with n=5: f(5)=−2f(5−1)+1 f(5)=−2f(4)+1 f(5)=−2(−61)+1 f(5)=122+1 f(5)=123