College

The exponential function [tex] f [/tex] is represented by the table:

[tex]
\begin{array}{cccccc}
x & -2 & -1 & 0 & 1 & 2 \\
f(x) & -46 & -22 & -10 & -4 & -1
\end{array}
[/tex]

Function [tex] g [/tex] is represented by the equation:

[tex]
g(x) = -18\left(\frac{1}{3}\right)^x + 2
[/tex]

Which statement correctly compares the two functions on the interval [tex] [-1, 2] [/tex]?

A. Both functions are increasing, but function [tex] g [/tex] increases at a faster average rate.

B. Only function [tex] f [/tex] is increasing, and only function [tex] f [/tex] is negative.

C. Both functions are increasing, but function [tex] f [/tex] increases at a faster average rate.

D. Only function [tex] f [/tex] is increasing, but both functions are negative.

Answer :

To compare the functions [tex]\(f\)[/tex] and [tex]\(g\)[/tex] on the interval [tex]\([-1, 2]\)[/tex], we need to look at both their behavior (whether they are increasing or decreasing) and their rates of change.

1. Analyze Function [tex]\(f\)[/tex]:
- From the table, the values for function [tex]\(f\)[/tex] over the interval [tex]\([-1, 2]\)[/tex] are: [tex]\(-22, -10, -4, -1\)[/tex].
- These values are increasing because each subsequent value is larger than the previous one. Therefore, function [tex]\(f\)[/tex] is increasing on the interval [tex]\([-1, 2]\)[/tex].

2. Analyze Function [tex]\(g\)[/tex]:
- The equation for function [tex]\(g\)[/tex] is [tex]\(g(x) = -18\left(\frac{1}{3}\right)^x + 2\)[/tex].
- On evaluating [tex]\(g(x)\)[/tex] for [tex]\( x = -1, 0, 1, 2\)[/tex], we determine that [tex]\(g\)[/tex] is also increasing over the interval [tex]\([-1, 2]\)[/tex].

3. Compare the Average Rates of Change:
- The rate of change is essentially the slope when considering the changes over an interval.
- For both functions, calculate the average rate of change over the interval [tex]\([-1, 2]\)[/tex]:
- Function [tex]\(f\)[/tex] has a steady increase in values, showing it's consistently increasing.
- Function [tex]\(g\)[/tex] is based on an exponential decay modified by translations, but across this specific interval, it is increasing too.

4. Comparison:
- Once both functions are confirmed to be increasing, compare their rates of increase.
- Function [tex]\(g\)[/tex] increases at a faster average rate than function [tex]\(f\)[/tex].

Based on this analysis, the correct statement is:

A. Both functions are increasing, but function [tex]\(g\)[/tex] increases at a faster average rate.

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