1. The problem statement, all variables and given/known data Find the unit vector perpendicular to the level curve of f(x,y) = x2y-10xy-9y2 at (2,-1) 2. Relevant equations Gradient 3. The attempt at a solution I'm not sure what it's asking. Wouldn't this just be the gradient of f(x,y) evaluated at (2,-1) then normalized? or am I missing something?