Question

Find the 22nd term of the arithmetic sequence whose common difference is d =3 and whose first term is a_1=-20

Answer 1

1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,58,61,64,67,70,73,76,79,82,85,88,91,94,97,100

f(n) = 1 + 3(n-1) = 1 + 3n - 3 = 3n -2

f(22) = 3(22)-2 = 66-2 = 64