College

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, but both functions are 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, and only function [tex] f [/tex] is negative.

Answer :

To solve this problem and compare the two functions [tex]\( f \)[/tex] and [tex]\( g \)[/tex] on the interval [tex]\([-1, 2]\)[/tex], let's systematically analyze their behavior.

### Step 1: Analyze Function [tex]\( f \)[/tex]

The function [tex]\( f \)[/tex] is represented by a table with these values:

- [tex]\( f(-1) = -22 \)[/tex]
- [tex]\( f(0) = -10 \)[/tex]
- [tex]\( f(1) = -4 \)[/tex]
- [tex]\( f(2) = -1 \)[/tex]

#### Determine if [tex]\( f \)[/tex] is Increasing or Decreasing

Let's check if [tex]\( f(x) \)[/tex] is increasing over the interval from [tex]\(-1\)[/tex] to [tex]\(2\)[/tex]:

- From [tex]\( x = -1 \)[/tex] to [tex]\( x = 0 \)[/tex]: [tex]\( f(-1) < f(0) \)[/tex] ([tex]\(-22 < -10\)[/tex])
- From [tex]\( x = 0 \)[/tex] to [tex]\( x = 1 \)[/tex]: [tex]\( f(0) < f(1) \)[/tex] ([tex]\(-10 < -4\)[/tex])
- From [tex]\( x = 1 \)[/tex] to [tex]\( x = 2 \)[/tex]: [tex]\( f(1) < f(2) \)[/tex] ([tex]\(-4 < -1\)[/tex])

Since each value of [tex]\( f(x) \)[/tex] is less than the next, function [tex]\( f \)[/tex] is increasing on the interval [tex]\([-1, 2]\)[/tex].

#### Determine if [tex]\( f \)[/tex] is Negative

All values [tex]\(-22\)[/tex], [tex]\(-10\)[/tex], [tex]\(-4\)[/tex], [tex]\(-1\)[/tex] are negative, so [tex]\( f(x) \)[/tex] is negative on the entire interval [tex]\([-1, 2]\)[/tex].

### Step 2: Analyze Function [tex]\( g \)[/tex]

The function [tex]\( g \)[/tex] is defined by the equation:

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

#### Determine if [tex]\( g \)[/tex] is Increasing or Decreasing

We check the values at points [tex]\(-1\)[/tex] to [tex]\(2\)[/tex]:

- [tex]\( g(-1) = -18(3) + 2 = -54 + 2 = -52 \)[/tex]
- [tex]\( g(0) = -18(1) + 2 = -18 + 2 = -16 \)[/tex]
- [tex]\( g(1) = -18\left(\frac{1}{3}\right) + 2 = -6 + 2 = -4 \)[/tex]
- [tex]\( g(2) = -18\left(\frac{1}{9}\right) + 2 = -2 + 2 = 0 \)[/tex]

Let's check if [tex]\( g(x) \)[/tex] is increasing:

- From [tex]\( x = -1 \)[/tex] to [tex]\( x = 0 \)[/tex]: [tex]\( g(-1) < g(0) \)[/tex] ([tex]\(-52 < -16\)[/tex])
- From [tex]\( x = 0 \)[/tex] to [tex]\( x = 1 \)[/tex]: [tex]\( g(0) < g(1) \)[/tex] ([tex]\(-16 < -4\)[/tex])
- From [tex]\( x = 1 \)[/tex] to [tex]\( x = 2 \)[/tex]: [tex]\( g(1) < g(2) \)[/tex] ([tex]\(-4 < 0\)[/tex])

Function [tex]\( g \)[/tex] is increasing on the interval [tex]\([-1, 2]\)[/tex].

#### Determine if [tex]\( g \)[/tex] is Negative

At [tex]\( x = 2 \)[/tex], [tex]\( g(2) = 0 \)[/tex], which is not negative. Therefore, function [tex]\( g \)[/tex] is not completely negative over this interval.

### Comparison

- Increasing Behavior: Both [tex]\( f \)[/tex] and [tex]\( g \)[/tex] are increasing.
- Negativity: [tex]\( f \)[/tex] is negative throughout, but [tex]\( g \)[/tex] is not.

### Conclusion

The correct statement that accurately compares the two functions on the interval [tex]\([-1, 2]\)[/tex] is:

D. Only function [tex]\( f \)[/tex] is increasing, and only function [tex]\( f \)[/tex] is negative.

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