Question

If an = 2n^2+5 then find a3

Answer 1

Answer:

23

Step-by-step explanation:

$an \: = 2 {n}^{2} + 5 \\ a3 = 2( {3}^{2}) + 5 \\ \: \: \: \: \: \: = 2 \times 9 + 5 \\ \: \: \: \: \: \: = 18 + 5 \\ \: \: \: \: \: \: = 23 \\ = = = = = = = = = =$

Answer 2

Answer:

an = 2n^2+5

let n =3

a3 = 2(3)^2 + 5

= 18+5

= 23