[[☃ image 1]] Suppose you take the graph $f(x, y) = x^2 y$, and you slice it with a vertical plane in the direction of the vector $\vec{\text{v}} = \left[\begin{array}{c} 1 \\ 1 \end{array} \right]$. This plane intersects the graph of $f(x, y)$ along a curve (pictured in red above). What is the slope of that curve at the point $(-1, -1, -1)$? [[☃ expression 1]]