I see that there is a description of double scaling above. I assume that this is what "the product rule" refers to, but it is never explicitly labeled as such. Maybe giving the paragraph above Reverse a bold heading titled "The Product Rule" would help with this.
Maybe insert an equation style definition of the unit vector here, before showing that it has magnitude 1.
^v=1|v|v=v|v|.
Alright, I've reworked this part, do you think it is better now?
I see that there is a description of double scaling above. I assume that this is what "the product rule" refers to, but it is never explicitly labeled as such. Maybe giving the paragraph above Reverse a bold heading titled "The Product Rule" would help with this.