The graph shows a polynomial function. The number of turning points suggests the degree of the polynomial. The graph has three turning points, indicating a polynomial of degree 4.
Step 2: Match the Degree with the Options
From the given options, identify which functions are of degree 4:
\( f(x) = -\frac{1}{3}x^4 + 4x^2 \)
\( f(x) = x^4 + 2x^3 \)
Step 3: Analyze the Leading Coefficient
The graph shows that the polynomial opens downwards on both ends, indicating a negative leading coefficient. Therefore, the correct function must have a negative leading coefficient for the highest degree term.
Final Answer
The correct function is:
\[ f(x) = -\frac{1}{3}x^4 + 4x^2 \]