The standard diameter of a golf ball is [tex][tex]$42.67 \, \text{mm}$[/tex][/tex]. A golf ball factory does quality control on the balls it manufactures. Golf balls are randomly measured to ensure the correct size. One day, an inspector decides to stop production if the discrepancy in diameter is more than [tex][tex]$0.002 \, \text{mm}$[/tex][/tex]. Which function could represent this situation?

A. [tex]f(x) = x - |42.67|[/tex]
B. [tex]f(x) = |x| - 42.67[/tex]
C. [tex]f(x) = |42.67 - x|[/tex]
D. [tex]f(x) = 42.67 - |x|[/tex]



Answer :

To represent the situation where an inspector decides to stop production if the discrepancy in the diameter of a golf ball is more than [tex]\(0.002 \text{ mm}\)[/tex], we need a function that measures the absolute difference between the measured diameter [tex]\(x\)[/tex] and the standard diameter, which is [tex]\(42.67 \text{ mm}\)[/tex].

The absolute difference can be represented mathematically as:

[tex]\[ f(x) = |42.67 - x| \][/tex]

Let's break down why this function is appropriate:

1. Absolute Value: The absolute value ensures that the result is always a non-negative number, reflecting the size of the discrepancy irrespective of whether the measured diameter [tex]\(x\)[/tex] is larger or smaller than [tex]\(42.67 \text{ mm}\)[/tex].

2. Difference in Diameters: The expression within the absolute value, [tex]\(42.67 - x\)[/tex], represents the direct difference between the standard diameter (42.67 mm) and the measured diameter [tex]\(x\)[/tex].

Given the choices:
- [tex]\[ f(x) = x - |42.67| \][/tex]: This does not account for the absolute difference between the specific measured diameter [tex]\(x\)[/tex] and the standard diameter. Also, [tex]\(|42.67|\)[/tex] is just [tex]\(42.67\)[/tex] as it is a positive constant, so this bears no relation to the measurement [tex]\(x\)[/tex].
- [tex]\[ f(x) = |x| - 42.67 \][/tex]: This expression does not give the absolute difference directly. It first takes the modulus of [tex]\(x\)[/tex] which can distort the intention behind calculating discrepancy.
- [tex]\[ f(x) = |42.67 - x| \][/tex]: This correctly measures the absolute difference between the measured diameter and the standard diameter.

Hence, the correct function to represent the situation of measuring the discrepancy is:

[tex]\[ f(x) = |42.67 - x| \][/tex]

This function matches the requirements of measuring the absolute discrepancy between the measured diameter and the standard diameter. Therefore, we use [tex]\( f(x) = |42.67 - x| \)[/tex].