Given:
The sequence is:
[tex]17,-\dfrac{17}{8},\dfrac{17}{27},-\dfrac{17}{64},\dfrac{17}{125},...[/tex]
To find:
The formula for the nth term in the given sequence.
Solution:
We have,
[tex]17,-\dfrac{17}{8},\dfrac{17}{27},-\dfrac{17}{64},\dfrac{17}{125},...[/tex]
The given sequence can be written as
[tex]\dfrac{17}{1^3},-\dfrac{17}{2^3},\dfrac{17}{3^3},-\dfrac{17}{4^3},\dfrac{17}{5^3},...[/tex]
The sign are alternative and the absolute value of each term can be defined by the expression [tex]\dfrac{17}{n^3}[/tex], where n is a natural number.
So, the required formula is:
[tex]a_n=(-1)^{n+1}\dfrac{17}{n^3}[/tex]
Therefore, the formula for nth term in the given sequence is [tex]a_n=(-1)^{n+1}\dfrac{17}{n^3}[/tex].
