Select all the correct answers.

The cube root of [tex]r[/tex] varies inversely with the square of [tex]s[/tex]. Which two equations model this relationship?

A. [tex]\sqrt[3]{r}=\frac{k}{s^2}[/tex]

B. [tex]s^{\frac{1}{2}} r^3=k[/tex]

C. [tex]\frac{s^2}{\sqrt[3]{r}}=k[/tex]

D. [tex]\sqrt[3]{r}=s^2 k[/tex]

E. [tex]s^2 r^{\frac{1}{3}}=k[/tex]

F. [tex]\frac{\sqrt[3]{r}}{s^3}=k[/tex]



Answer :

To determine which equations accurately model the relationship where the cube root of \( r \) varies inversely with the square of \( s \), let's analyze how this relationship can be expressed mathematically.

### Step-by-Step Solution:

1. Relationship Statement: The statement "the cube root of \( r \) varies inversely with the square of \( s \)" can be expressed as:
[tex]\[ \sqrt[3]{r} = \frac{k}{s^2} \][/tex]
where \( k \) is a constant.

2. Rewrite Relationship:
- Begin with the given expression:
[tex]\[ \sqrt[3]{r} = \frac{k}{s^2} \][/tex]
- Multiplying both sides by \( s^2 \) to remove the fraction:
[tex]\[ s^2 \sqrt[3]{r} = k \][/tex]

3. Examine Options:
- Option 1: \(\sqrt[3]{r} = \frac{k}{s^2}\)
- This directly matches our derived equation.
- Correct.
- Option 2: \(s^{\frac{1}{2}} r^3 = k\)
- Not compatible with the inverse cube root and square relationship.
- Incorrect.
- Option 3: \(\frac{s^2}{\sqrt[3]{r}} = k\)
- In radians, this does not match any form we derived.
- Incorrect.
- Option 4: \(\sqrt[3]{r} = s^2 k\)
- Inconsistent with the original inverse relationship.
- Incorrect.
- Option 5: \(s^2 r^{\frac{1}{3}} = k\)
- This is simply another form of our modified equation \(s^2 \sqrt[3]{r} = k\).
- Correct.
- Option 6: \(\frac{\sqrt[3]{r}}{s^3} = k\)
- This does not adhere to the original inverse relationship.
- Incorrect.

### Correct Equations:

Based on the above evaluations, the two equations that accurately model the given relationship are:

[tex]\[ \sqrt[3]{r} = \frac{k}{s^2} \][/tex]
and
[tex]\[ s^2 r^{\frac{1}{3}} = k \][/tex]

Thus, the correct answers are:
Option 1 and Option 5.