For $f ( x , y ) = x ^ { 2 } y$

Multiple Choice

For $f ( x , y ) = x ^ { 2 } y$ find a line in the x direction tangent to the surface defined by f at (1,2) .

A) $\vec { r } ( t ) = \langle 1,2,2 \rangle + t \langle 0,0,4 \rangle$
B) $\vec { r } ( t ) = \langle 1,2,2 \rangle + t \langle 0,0,2 \rangle$
C) $\vec { r } ( t ) = \langle 1,2,2 \rangle + t \langle 0,0,1 \rangle$
D) $\vec { r } ( t ) = \langle 1,2,2 \rangle + t \langle 4,1,0 \rangle$