Q. If a1=2,a2=1 and an=2an−1+an−2 then find the value of a5.Answer:
Understand the formula: Understand the recursive formula and initial conditions.The recursive formula given is an=2an−1+an−2, which means each term is the sum of twice the previous term and the term before that. We are given a1=2 and a2=1.
Find a3: Find the value of a3 using the recursive formula.a3=2a2+a1a3=2(1)+2a3=2+2a3=4
Find a4: Find the value of a4 using the recursive formula.a4=2a3+a2a4=2(4)+1a4=8+1a4=9
Find a5: Find the value of a5 using the recursive formula.a5=2a4+a3a5=2(9)+4a5=18+4a5=22
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