Find the Directional Derivative Of $f ( x , y ) = 2 \sqrt { x } - y ^ { 3 }$

question 72

Multiple Choice

Find the directional derivative of $f ( x , y ) = 2 \sqrt { x } - y ^ { 3 }$ at the point $( 1,3 )$ in the direction toward the point $( 3,1 )$ .
Select the correct answer.

• A) \(7 \sqrt { 2 }\)
• B) \(14 \sqrt { 2 }\)
• C) \(\sqrt { 2 }\)
• D) 28
• E) none of these

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