Find the directional derivative of = xy2 + yz3 at (1, -1, 1), towards the point (2, 1, -1).

Find the directional derivative of = xy2 + yz3 at (1, -1, 1), toward

1.	Find the directional derivative of = xy2 + yz3 at (1, -1, 1), towards the point (2, 1, -1).
A.	( frac{5}{3} )
B.	( frac{-5}{3} )
C.	( frac{7}{3} )
D.	( frac{1}{3} )
Answer» B. ( frac{-5}{3} )

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Find the directional derivative of = xy2 + yz3 at (1, -1, 1), towards the point (2, 1, -1).