Question

Find the a15 of the sequence 7/8, 1 / 2, 1 / 8, -1 / 4​

Answer 1

=-485/1944( Decimal: 0.249486)

Explanation:

7/81/21/8-1/4

Answer 2

The term a15 of the sequence is
`a_(15)=-(35)/(8)`.

Explanation:

The given sequence is

`(7)/(8),(1)/(2),(1)/(8),(-1)/(4)`

It it an arithmetic sequence because the difference between two consecutive terms are same.

The first term of the given AP is

`a=(7)/(8)`

The common difference is

`d=(1)/(2)-(7)/(8)=-(3)/(8)`

The nth term of an AP is

`a_n=a+(n-1)d`

where, a is first term and d is common difference.

`a_(15)=(7)/(8)+(15-1)(-(3)/(8))`

`a_(15)=(7)/(8)-(14)((3)/(8))`

`a_(15)=(7)/(8)-(21)/(4)`

`a_(15)=-(35)/(8)`

Therefore the term a15 of the sequence is
`a_(15)=-(35)/(8)`.