www.jiskha.com/questions/1806430/Can-someone-help-me-with-the-following-Prove-that-grad-2-f-r-D-2-dr-2-2-r

Answer 1

I've been thinking on this, but been kinda busy. Surely by now, someone in your class has solved this, or your teacher has explained it. ??

In any case, I was thinking of following this idea:

∇×(∇×A) = ∇(∇•A) - ∇²A

where A is any vector function. You can show this by expanding out the various operators. I haven't checked yet to see whether it matches your problem...

Answer 2

Unfortunately, no one still haven't solved this one?

Could you please look into it?