Quote:
Originally Posted by erezarnon
The problem asks us to prove that the optimal column vector is in the opposite direction of the inverse of the Hessian times the gradient.
But didn't the chapter prove that the optimal column vector is in the opposite direction of the gradient?

The chapter shows that the optimal column vector, subject to the firstorder Taylor's approximation, is the negative gradient. Problem 3.7(d) asks you to consider secondorder Taylor's approximation instead, though.
Hope this helps.