Select the correct answer.

Which type of sequence is represented by the given table?

\begin{tabular}{|c|c|c|c|c|}
\hline
[tex]$x$[/tex] & 1 & 2 & 3 & 4 \\
\hline
[tex]$y$[/tex] & 4 & -9.6 & 23.04 & -55.296 \\
\hline
\end{tabular}

A. The table represents a geometric sequence because the successive [tex]$y$[/tex]-values have a common ratio of -2.4.

B. The table represents an arithmetic sequence because the successive [tex]$y$[/tex]-values have a common difference of -17.

C. The table represents an arithmetic sequence because the successive [tex]$y$[/tex]-values have a common difference of 4.2.

D. The table represents a geometric sequence because the successive [tex]$y$[/tex]-values have a common ratio of 0.4.



Answer :

To determine the type of sequence represented in the table, let's analyze the values of [tex]\( y \)[/tex] corresponding to the given values of [tex]\( x \)[/tex]:

[tex]\[ \begin{array}{|c|c|c|c|c|} \hline x & 1 & 2 & 3 & 4 \\ \hline y & 4 & -9.6 & 23.04 & -55.296 \\ \hline \end{array} \][/tex]

We need to check if these values form a geometric sequence by examining the common ratio between successive [tex]\( y \)[/tex]-values. In a geometric sequence, the ratio of [tex]\( y_{n+1} \)[/tex] to [tex]\( y_n \)[/tex] (where [tex]\( y_n \)[/tex] is the n-th term) should be constant.

Firstly, let's calculate the ratios between successive terms:

1. Ratio between the second term and the first term:
[tex]\[ \frac{y_2}{y_1} = \frac{-9.6}{4} = -2.4 \][/tex]

2. Ratio between the third term and the second term:
[tex]\[ \frac{y_3}{y_2} = \frac{23.04}{-9.6} = -2.4 \][/tex]

3. Ratio between the fourth term and the third term:
[tex]\[ \frac{y_4}{y_3} = \frac{-55.296}{23.04} = -2.4 \][/tex]

Since the ratio between successive [tex]\( y \)[/tex]-values is consistently [tex]\(-2.4\)[/tex], we can confirm that the given sequence is a geometric sequence with a common ratio of [tex]\(-2.4\)[/tex].

Thus, the correct answer is:
A. The table represents a geometric sequence because the successive [tex]\( y \)[/tex]-values have a common ratio of [tex]\(-2.4\)[/tex].