Question

Find the sum of the arithmetic series given a1=8,a14=99,n=14.

Answer 1

The sum of the series is 749

Explanation:

Given

`a_1 = 8`

`a_(14) = 99`

`n = 14`

Required

The sum of the series

This is calculated using:

`S_n = (n)/(2)[a_1 + a_n]`

Substitute 14 for n

`S_(14) = (14)/(2)[a_1 + a_(14)]`

`S_(14) = 7[a_1 + a_(14)]`

Substitute values for a1 and a14

`S_(14) = 7[8 + 99]`

`S_(14) = 7*107`

`S_(14) = 749`