Answered

Select the correct answer.

Consider functions [tex]\( f \)[/tex] and [tex]\( g \)[/tex]:
[tex]\[
\begin{array}{l}
f(z) = \log (z-1) \\
g(z) = \frac{1}{3} x^2 - 4
\end{array}
\][/tex]

Which statement gives the best approximation of the solutions of the equation [tex]\( f(x) = g(x) \)[/tex]?

A. The solutions are where the graphs of the functions intersect at [tex]\( x \approx -3.464 \)[/tex] and [tex]\( x \approx 3.464 \)[/tex].

B. The solutions are where the graphs of the functions cross the [tex]\( x \)[/tex]-axis at [tex]\( x \approx 4 \)[/tex] and [tex]\( x \approx 0.422 \)[/tex].

C. The solutions are where the graphs of the functions intersect at [tex]\( x \approx 1 \)[/tex] and [tex]\( x \approx 3.642 \)[/tex].

D. The solutions are where the graphs of the functions cross the [tex]\( x \)[/tex]-axis at [tex]\( x \approx -3.464 \)[/tex] and [tex]\( x \approx 3.642 \)[/tex].



Answer :

To find the approximate solutions of the equation [tex]\( f(x) = g(x) \)[/tex] for the given functions [tex]\( f \)[/tex] and [tex]\( g \)[/tex]:

[tex]\[ f(z) = \log(z-1) \][/tex]

[tex]\[ g(z) = \frac{1}{3}x^2 - 4 \][/tex]

we will equate [tex]\( f(z) \)[/tex] and [tex]\( g(z) \)[/tex]:

[tex]\[ \log(z-1) = \frac{1}{3}x^2 - 4 \][/tex]

We will solve this equation step-by-step.

Step 1: Isolate the logarithm
[tex]\[ \log(z-1) = \frac{1}{3}x^2 - 4 \][/tex]

Step 2: Convert the logarithmic equation to an exponential equation
By recalling that if [tex]\(\log_b(a) = c\)[/tex], then [tex]\(a = b^c\)[/tex], we get:
[tex]\[ z - 1 = e^{\frac{1}{3}x^2 - 4} \][/tex]

Step 3: Isolate [tex]\( z \)[/tex]
[tex]\[ z = e^{\frac{1}{3}x^2 - 4} + 1 \][/tex]

Step 4: Solve for [tex]\( x \)[/tex]
To solve for [tex]\( x \)[/tex], we typically need numerical methods or software tools, but for the purpose of this task, we observe that the equation is transcendental and does not yield simple closed-form solutions analytically. Instead, we look at the graphing approach or numerical technique (like finding points where functions intersect).

Given the options:
- Option A. The solutions are where the graphs of the functions intersect at [tex]\(x \approx -3.464 \)[/tex] and [tex]\( x \approx 3.464\)[/tex].
- Option B. The solutions are where the graphs of the functions cross the [tex]\(x\)[/tex]-axis at [tex]\(x \approx 4\)[/tex] and [tex]\(x \approx 0.422\)[/tex].
- Option C. The solutions are where the graphs of the functions intersect at [tex]\(x \approx 1\)[/tex] and [tex]\(x \approx 3.642\)[/tex].
- Option D. The solutions are where the graphs of the functions cross the [tex]\(x\)[/tex]-axis at [tex]\(x \approx -3.464\)[/tex] and [tex]\(x \approx 3.642\)[/tex].

Analyzing the solutions numerically or through simulation, the approximate solutions for the intersection points where [tex]\(f(x) = g(x)\)[/tex] yield [tex]\( x \approx 4 \)[/tex] and [tex]\( x \approx 0.422 \)[/tex].

Therefore, the correct answer is:

B. The solutions are where the graphs of the functions cross the [tex]\(x\)[/tex]-axis at [tex]\(x \approx 4\)[/tex] and [tex]\(x \approx 0.422\)[/tex].