# Thread: Divergence and Derivatives - Check my work + One minor question (Romsek Friendly)

1. ## Divergence and Derivatives - Check my work + One minor question (Romsek Friendly)

Question - imgur: the simple image sharer

Answers - imgur: the simple image sharer

I am slightly unsure what to do with (c), do we use the same limits as from part (b)?

Anyone?

3. ## Re: Divergence and Derivatives - Check my work + One minor question (Romsek Friendly)

for (b) just evaluate the gradient at that point

for (c) you take the directional derivative which is the gradient dot the directional vector

I don't see how you can do (c) unless they tell you a point to take the derivative at.

4. ## Re: Divergence and Derivatives - Check my work + One minor question (Romsek Friendly)

Originally Posted by romsek
for (b) just evaluate the gradient at that point

for (c) you take the directional derivative which is the gradient dot the directional vector

I don't see how you can do (c) unless they tell you a point to take the derivative at.
That's why I was thinking possibly we use the same point as in b maybe?

5. ## Re: Divergence and Derivatives - Check my work + One minor question (Romsek Friendly)

that would be my guess