Respuesta :

Given:

The sequence is:

[tex]6, -24, 96, -384,...[/tex]

To find:

The explicit formula for the given sequence and then find the 16th term.

Solution:

We have,

[tex]6, -24, 96, -384,...[/tex]

The ratio between two consecutive terms are:

[tex]\dfrac{-24}{6}=-4[/tex]

[tex]\dfrac{96}{-24}=-4[/tex]

[tex]\dfrac{-384}{96}=-4[/tex]

The given sequence has a common ratio. So, the given sequence is a geometric sequence with first term 6 and common ratio [tex]-4[/tex].

The explicit formula of a geometric sequence is:

[tex]a_n=ar^{n-1}[/tex]

Where, a is the first term and r is the common ratio.

Putting [tex]a=6, r=-4[/tex] in the above formula, we get

[tex]a_n=6(-4)^{n-1}[/tex]

We need to find the 16th term. So, put [tex]n=16[/tex] in the above formula.

[tex]a_n=6(-4)^{16-1}[/tex]

[tex]a_n=6(-4)^{15}[/tex]

[tex]a_n=6(-1073741824)[/tex]

[tex]a_n=-6442450944[/tex]

Therefore, the explicit formula for the given sequence is  [tex]a_n=6(-4)^{n-1}[/tex] and 16th term of the given sequence is [tex]-6.442450944[/tex].

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