Use the Limit Definition of the Partial Derivative to Compute $\text { Find } \frac { \partial f } { \partial y } \text { at the point } ( - 10,1 ) : f ( x , y ) = 9 - 10 x y + 3 x y ^ { 2 }$

Use the limit definition of the partial derivative to compute the indicated partial derivative of the function at the specified point.
- $\text { Find } \frac { \partial f } { \partial y } \text { at the point } ( - 10,1 ) : f ( x , y ) = 9 - 10 x y + 3 x y ^ { 2 }$