Use the Limit Definition of the Partial Derivative to Compute $\text { Find } \frac { \partial f } { \partial y } \text { at the point } ( 3 , - 9,9 ) : f ( x , y , z ) = 2 x ^ { 2 } y + 2 y ^ { 2 } + 10 z$

Essay

Use the limit definition of the partial derivative to compute the indicated partial derivative of the function at the specified point.
- $\text { Find } \frac { \partial f } { \partial y } \text { at the point } ( 3 , - 9,9 ) : f ( x , y , z ) = 2 x ^ { 2 } y + 2 y ^ { 2 } + 10 z$