Question

Find an explicit formula for the arithmetic sequence -5,13,31,49,...

Note: the first term should be b(1).

b(n) = ?

Answer 1

Explanation:

b(n) = b(1) + (n-1) d, where d is the difference,

d = 13-(-5) = 18

b(n) = (-5) + (n-1)(18)

= -5 +18n -18

b(n) = 18n -23