Find the first six terms of the sequence. a1 = 4, an = 2 • an-1

Find the first six terms of the sequence. a1 = - 4, an = an-1 + 7

Hello:

1) a1 = 4, an = 2 • an-1

this is a geometric sequence the first terme is; a1 = 4 and common ratio : r = 2

the general term is : an = a1 * r^ (n-1)

an = 4 * 2^ (n-1) ... (*)

the first six terms is : a1, a2, a3, a4, a5, a6

put; n = 1, 2, 3, 4, 5 in : (*) ... calculate.

2) same idea; a1 = - 4, an = an-1 + 7 but you are the arithmetic sequence the first terme is; a1 = - 4 and common difference : r = 7

the general term is = an = a 1 + (n-1) r

an = - 4 + 7 (n-1)

an = 7n - 11 ... (**) ... calculate