Select the correct answer.

\begin{tabular}{|c|c|}
\hline
[tex]$x$[/tex] & [tex]$f(x)$[/tex] \\
\hline
3.0 & 4.0 \\
\hline
3.5 & -0.2 \\
\hline
4.0 & -0.8 \\
\hline
4.5 & 0.1 \\
\hline
5.0 & 0.6 \\
\hline
5.5 & 0.7 \\
\hline
\end{tabular}

For the given table of values for a polynomial function, where must the zeros of the function lie?

A. between 3.0 and 3.5 and between 4.0 and 4.5
B. between 3.5 and 4.0 and between 4.0 and 4.5
C. between 3.5 and 4.0 and between 5.0 and 5.5
D. between 4.0 and 4.5 and between 4.5 and 5.0



Answer :

To determine where the zeros of the function lie, we need to identify the intervals where the function changes sign. A sign change between two consecutive values of [tex]\( f(x) \)[/tex] indicates that a zero exists between the corresponding [tex]\( x \)[/tex]-values.

Given the table:

[tex]\[ \begin{array}{|c|c|} \hline x & f(x) \\ \hline 3.0 & 4.0 \\ \hline 3.5 & -0.2 \\ \hline 4.0 & -0.8 \\ \hline 4.5 & 0.1 \\ \hline 5.0 & 0.6 \\ \hline 5.5 & 0.7 \\ \hline \end{array} \][/tex]

We need to check each consecutive pair to identify where the function changes from positive to negative or from negative to positive.

1. Between [tex]\( x = 3.0 \)[/tex] and [tex]\( x = 3.5 \)[/tex]:
- [tex]\( f(3.0) = 4.0 \)[/tex] (positive)
- [tex]\( f(3.5) = -0.2 \)[/tex] (negative)
- There is a sign change from positive to negative.
- Therefore, a zero lies between [tex]\( x = 3.0 \)[/tex] and [tex]\( x = 3.5 \)[/tex].

2. Between [tex]\( x = 3.5 \)[/tex] and [tex]\( x = 4.0 \)[/tex]:
- [tex]\( f(3.5) = -0.2 \)[/tex] (negative)
- [tex]\( f(4.0) = -0.8 \)[/tex] (negative)
- No sign change.

3. Between [tex]\( x = 4.0 \)[/tex] and [tex]\( x = 4.5 \)[/tex]:
- [tex]\( f(4.0) = -0.8 \)[/tex] (negative)
- [tex]\( f(4.5) = 0.1 \)[/tex] (positive)
- There is a sign change from negative to positive.
- Therefore, a zero lies between [tex]\( x = 4.0 \)[/tex] and [tex]\( x = 4.5 \)[/tex].

4. Between [tex]\( x = 4.5 \)[/tex] and [tex]\( x = 5.0 \)[/tex]:
- [tex]\( f(4.5) = 0.1 \)[/tex] (positive)
- [tex]\( f(5.0) = 0.6 \)[/tex] (positive)
- No sign change.

5. Between [tex]\( x = 5.0 \)[/tex] and [tex]\( x = 5.5 \)[/tex]:
- [tex]\( f(5.0) = 0.6 \)[/tex] (positive)
- [tex]\( f(5.5) = 0.7 \)[/tex] (positive)
- No sign change.

Based on this analysis, the zeros of the function must lie in the intervals:
- Between [tex]\( 3.0 \)[/tex] and [tex]\( 3.5 \)[/tex]
- Between [tex]\( 4.0 \)[/tex] and [tex]\( 4.5 \)[/tex]

Therefore, the correct answer is:

A. between 3.0 and 3.5 and between 4.0 and 4.5.