Find the Direction in Which the Function $f ( x , y ) = x ^ { 4 } y - x ^ { 3 } y ^ { 2 }$

Short Answer

Find the direction in which the function $f ( x , y ) = x ^ { 4 } y - x ^ { 3 } y ^ { 2 }$ decreases fastest at the point $( 2 , - 1 )$ .