Now, what's the gradient vector?
The gradient vector would be going perpendicular to the level.
Does the gradient vector, why is the gradient vector perpendicular in one direction rather than the other?
And we have learned how to package partial derivatives into a vector, the gradient vector.
If I fix a point, then the gradient vector at that point is given to me.
And we know how to find a normal vector to the level set, namely the gradient vector is always perpendicular to the level set.
OK, so the new definition for today is the definition of the gradient vector. And, our goal will be to understand a bit better what does this vector mean?
