Find the Largest Open Interval Where the Function Is Changing $\quad f ( x ) = x ^ { 3 } - 4 x$

question 354

Multiple Choice

Find the largest open interval where the function is changing as requested.
-Decreasing $\quad f ( x ) = x ^ { 3 } - 4 x$

• A) \(\left( - \infty , - \frac { 2 \sqrt { 3 } } { 3 } \right)\)
• B) \(( - \infty , \infty )\)
• C) \(\left( - \frac { 2 \sqrt { 3 } } { 3 } , \frac { 2 \sqrt { 3 } } { 3 } \right)\)
• D) \(\left( \frac { 2 \sqrt { 3 } } { 3 } , \infty \right)\)

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