To identify the factor \( k \) for the vertical compression from the function \( f(x) = x^3 + 2 \) to the function \( f(x) = \frac{1}{4} x^3 + \frac{1}{2} \), we need to analyze how the leading coefficient changes.
- The original function is \( f(x) = x^3 + 2 \) (the leading term is \( x^3 \) with a coefficient of 1).
- The new function is \( f(x) = \frac{1}{4} x^3 + \frac{1}{2} \) (the leading term now has a coefficient of \( \frac{1}{4} \)).
The leading coefficient has changed from 1 to \( \frac{1}{4} \).
The vertical compression factor \( k \) indicates how much the original function is compressed vertically. This can be determined by finding the ratio of the new leading coefficient to the original leading coefficient:
\[ k = \frac{\text{new coefficient}}{\text{original coefficient}} = \frac{\frac{1}{4}}{1} = \frac{1}{4} \]
Thus, the correct response is:
k equals \( \frac{1}{4} \).