Find a2 and a3.

Question

a₁=–3

a_n=a_n–1–8

Answer 1

Hello, Nat,

We know that a₁= –3.

We are told that a_n=a_(n–1) – 8, which says that the value for a_n is equal to the value of a_(n-1) minus 8. This means if we take the preceding value of n (n-1) and subract 8, we'll find a_n.

If a₁ = -3, then a₂ = a_(2-1) - 8 or a₂ = a₁ -8, and

a₂ = -3 -8 = -11

For a₃: a₃ = a₂ - 8 We know a₂ = -11, so a₃ = -19

This can be extended to other value of a₁.

I hope this helps,

Bob