# Quiz 8


Show that a search direction $\vp$ chosen as the solution of the linear system

is a descent direction where $\vp^T \vg < 0$ when $\mB$ is symmetric, positive definite.

### Solution

Either of:

after substituting $\vg = - \mB \vp$

or

after substituting $\vp = -\mB^{-1} \vg$.