using the standard notation of a and d,
a = 5
a+4d = 6.5
then 5 + d = 6.5
d = 1.5
sum(15) = (15/2)(2(5) + 14(1.5))
= 232.5
Find the partial sum Sn of the arithmetic sequence that satisfies the given conditions.
a2 = 5, a5 = 6.5, n = 15
S15 =
1 answer