Write a recursive formula and an explicit formula for each arithmetic sequence. 4. 9, 15, 21, 27, … 5. 1.5, 2.25, 3, 3.75, … 6. 7, 0, −7, −14,

Answer 1

#4. d = a_2 - a_1 = 15-9 = 6
a_1 = 9
a_n = a_n-1 + 6
a_n = 9 + 6(n-1) = 3+6n

Do the others in like wise