Question

If a1 ​=5 and an =an−1 +4 then find the value of a4 ​ .

Answer 1

17

Explanation:

You want to know the value of a4, given that a1 = 5 and a(n) = a(n-1) +4.

Arithmetic sequence

When a constant is added to each term to get the next term, the sequence is an arithmetic sequence. The terms can be found using the given equation:

a1 = 5

a2 = a1 +4 = 9

a3 = a2 +4 = 13

a4 = a3 +4 = 17

The value of a4 is 17.