Question

The formula r=3Vπ−−−√3
can be used to find the length of the radius of a cone in feet where the height is equal to the radius for a cone with a volume of V cubic feet.

What do the key features of the function reveal?

(1 point)
Responses

The function is an increasing function, so the length of the radius of the cone is increasing at a decreasing rate.
The function is an increasing function, so the length of the radius of the cone is increasing at a decreasing rate.

The function is an increasing function, so as the volume of the cylinder increases, the length of the radius of the cylinder increases at a constant rate.
The function is an increasing function, so as the volume of the cylinder increases, the length of the radius of the cylinder increases at a constant rate.

Due to the constraints, there is a minimum point at (0,0)
which indicates that when the volume of the cone is 10 cubic feet, the length of the radius of the cone is 0 feet.
Due to the constraints, there is a minimum point at open paren 0 comma 0 close paren which indicates that when the volume of the cone is 10 cubic feet, the length of the radius of the cone is 0 feet.

The range is r≤0
, so the radius of a cone only has negative values.
The range is r is less than or equal to 0 , so the radius of a cone only has negative values.
Skip to navigation

1 answer

To analyze the function \( r = \sqrt[3]{\frac{3V}{\pi}} \), we can start by recognizing that it relates the radius \( r \) of a cone to its volume \( V \).

  1. Increasing Function: The function is a cube root function. Since cubic roots are defined for all real numbers and are increasing, this means as the volume \( V \) increases, the radius \( r \) also increases.

  2. Rate of Increase: The rate at which \( r \) increases relative to \( V \) is not constant. The cube root function increases at a decreasing rate because the derivative of \( r \) with respect to \( V \) shows that as \( V \) becomes larger, the increase in \( r \) gets smaller (the slope of the curve decreases).

  3. Minimum Point: The minimum point at \( (0, 0) \) indicates that when the volume \( V \) is 0, the radius \( r \) is also 0. However, there is no indication in the question that when the volume is 10 cubic feet, the radius is 0; rather, this statement is incorrect. It should state that when \( V \) is 0, \( r \) is 0.

  4. Range of r: The range of radius \( r \) is non-negative (i.e., \( r \geq 0 \)). Negative values cannot be considered for a physical radius.

Based on this analysis, the correct choice would be aligned with these features. Among the provided responses, the first option correctly reflects that the function is increasing at a decreasing rate.

Correct Response: "The function is an increasing function, so the length of the radius of the cone is increasing at a decreasing rate."