In the questions below find a formula that generates the fol

In the questions below find a formula that generates the following sequence a1,a2,a3....

1) 5,9,13,17,21,....

2) 15,20,25,30,35,....

Solution

1: a1 = 5

d = 4

an = a1+(n-1)d

= 5+4n-4

= 4n + 1

2:

a1 = 15

d = 5

an = a1+(n-1)d

= 15+5n-5

= 5n + 10