1. ## Tough Gradient Proof. Help!

I was asked execute the proof shown in figure 1. I managed to prove what is in figure 2, but cannot make any headway on figure 3. Please Help.

2. Hello,
Originally Posted by Jensen
I was asked execute the proof shown in figure 1. I managed to prove what is in figure 2, but cannot make any headway on figure 3. Please Help.
Remember that $\frac{d(x^2)}{dx}=2x$
And hence $x \cdot dx=\frac{d(x^2)}{2}$

3. Thanks for the help. I also found a vector identity that worked nicely also.