Given an=2n+1−1,n≥1.
Then
an−1=2n−1+1−1=2n−1
an−2=2n−2+1−1=2n−1−1 Substitute
3an−1−2an−2=3(2n−1)−2(2n−1−1)
=3(2n)−3−2n+2=2n+1−1=an,n≥3 Since the last equation is true, then the explicit sequence {an} where an=2n+1−1,n≥1 is a solution of the recurrence relation:
an=3an−1−2an−2,n≥3
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