Question

If a1=3 and an=-2an find f 8

Answer 1

a₄ = 25

Explanation:

using the recursive formula
`a_(n)` = 2
`a_(n-1)` and a₁ = 4 , then

a₂ = 2a₁ - 1 = 2(4) - 1 = 8 - 1 = 7

a₃ = 2a₂ - 1 = 2(7) - 1 = 14 - 1 = 13

a₄ = 2a₃ - 1 = 2(13) - 1 = 26 - 1 = 25