Q. If a1=5 and an=−2an−1+1 then find the value of a4.Answer:
Identify first term: Identify the first term in the sequence.We are given that a1=5, which is the first term of the sequence.
Find second term: Use the recursive formula to find the second term, a2. The recursive formula is an=−2an−1+1. Substitute n=2 to find a2. a2=−2a1+1=−2(5)+1=−10+1=−9.
Find third term: Use the recursive formula to find the third term, a3. Substitute n=3 to find a3. a3=−2a2+1=−2(−9)+1=18+1=19.
Find fourth term: Use the recursive formula to find the fourth term, a4. Substitute n=4 to find a4. a4=−2a3+1=−2(19)+1=−38+1=−37.
More problems from Write and solve direct variation equations