# Math Help - directional derivatives

1. ## directional derivatives

I'm trying to find the directional derivative of the function:
$f(x,y,z)=x^3-xy^2-z
$

at the point $P_0(1,1,0)$

Any help would be appreciated. Thanks!

2. Originally Posted by btgebo
I'm trying to find the directional derivative of the function:
$f(x,y,z)=x^3-xy^2-z
$

at the point $P_0(1,1,0)$

Any help would be appreciated. Thanks!
Do you know the formula for calculating a directional derivative? Please quote it from your textbook or class notes.

3. Also, you need a direction in which to find the directional derivative.
The direction needs to be a unit vector.

4. thanks for the help guys. turns out the paper with the problem didn't have the (necessary) vector equation on it.

I figured it out once i got all the information