Find the indicated terms in each of the following sequences whose nth terms are:
$ a_{n}=(-1)^{n} n ; a_{3}, a_{5}, a_{8} $

Given:

$a_{n}=(-1)^{n} n$

To do:

We have to find $a_{3}, a_{5}$ and $a_{8}$.

Solution:

 To find $a_{3}$, we have to substitute $3$ in place of $n$ in $a_{n}=(-1)^{n} n$.

This implies,

$a_{3}=(-1)^{3} 3$

$=(-1)\times3$

$=-3$.

 To find $a_{5}$, we have to substitute $5$ in place of $n$ in $a_{n}=(-1)^{n} n$.

This implies,

$a_{5}=(-1)^{5} 5$

$=(-1)\times5$

$=-5$.

To find $a_{8}$, we have to substitute $8$ in place of $n$ in $a_{n}=(-1)^{n} n$.

This implies,

$a_{8}=(-1)^{8} 8$

$=1\times8$

$=8$.

Therefore, $a_{3}=-3, a_{5}=-5$ and $a_{8}=8$. 

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Updated on: 10-Oct-2022

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