e area of a circle can be represented by the function π

with domain
, where
is the radius of the circle. Which statement about this function is true?

A.
The function has a minimum.

B.
The function has two zeros.

C.
The function has no zeros.

D.
The function has a maximum.

1 answer

To analyze the function representing the area of a circle, which is given by the formula \( A = \pi r^2 \), where \( r \) is the radius of the circle, we need to consider the properties of this function.

  1. Domain: The radius \( r \) must be non-negative, so the domain of the function is \( r \geq 0 \).

  2. Behavior of the function: As \( r \) increases, the area \( A \) also increases. Therefore, the function is always increasing for \( r \geq 0 \) and its value is always positive for \( r > 0 \).

  3. Zeros of the function: The only zero of the function occurs when the area \( A = 0 \). This happens when \( r = 0 \). So, the function has one zero.

  4. Minimum and Maximum: The function \( A = \pi r^2 \) does reach a minimum value of 0 at \( r = 0 \) but does not have a maximum value since as \( r \) increases, \( A \) keeps increasing indefinitely.

Based on this analysis, the correct statement about the function is:

A. The function has a minimum.

This minimum occurs at \( r = 0 \), where the area of the circle is also 0. The function does not have two zeros, has one zero, and does not have a maximum.