A homeowner has an octagonal gazebo inside a circular area. Each vertex of the gazebo lies on the circumference of the circular area. The area that is inside the circle but outside the gazebo requires mulch. This area is represented by the function [tex]m(x)[/tex] where [tex]x[/tex] is the length of the radius of the circle in feet. The homeowner estimates that he will pay [tex]\$1.50[/tex] per square foot of mulch. This cost is represented by the function [tex]g(m)[/tex], where [tex]m[/tex] is the area requiring mulch.

[tex]\[
\begin{array}{l}
m(x) = x^2 - 2 \sqrt{2} x^2 \\
g(m) = 1.50m
\end{array}
\][/tex]

Which expression represents the cost of the mulch based on the radius of the circle?

A. [tex]1.50\left(x^2 - 2 \sqrt{2} x^2\right)[/tex]

B. [tex]\pi(1.50 x)^2 - 2 \sqrt{2} x^2[/tex]

C. [tex](13 x)^2 - 2 \sqrt{2}\left(1.50 x^2\right)[/tex]

D. [tex]1.50\left(\pi(1.50 x)^2 - 2 \sqrt{2}(1.50 x)^2\right)[/tex]



Answer :

To solve the problem, let's break it down step-by-step.

1. Finding the Area Inside but Outside the Gazebo (m(x)):
The given expression for the area that requires mulch is [tex]\( m(x) = x^2 - 2\sqrt{2} x^2 \)[/tex].

We can simplify this as follows:
[tex]\[ m(x) = x^2(1 - 2\sqrt{2}) \][/tex]

2. Finding the Total Cost of the Mulch (g(m)):
The cost function provided is [tex]\( g(m) = 1.50 \cdot m \)[/tex].

We need to substitute [tex]\( m(x) \)[/tex] into [tex]\( g(m) \)[/tex]:
[tex]\[ g(m(x)) = 1.50 \cdot (x^2(1 - 2\sqrt{2})) \][/tex]

Let's break it down:
[tex]\[ g(m(x)) = 1.50 \cdot x^2 \cdot (1 - 2\sqrt{2}) \][/tex]

Therefore, the expression that represents the cost of the mulch based on the radius of the circle [tex]\( x \)[/tex] is:
[tex]\[ 1.50 \left( x^2 - 2\sqrt{2} x^2 \right) \][/tex]

Among the given options, the correct one that matches our derived expression is:
[tex]\[ \boxed{1.50\left(x x^2 - 2\sqrt{2} x^2\right)} \][/tex]