- #1

particlezoo

- 113

- 4

**a**(x,y,z) and

**b**(x,y,z).

Let's say I have a scalar field f equal to

**a**•

**b**.

I want to find a clean-looking, simple way to express the directional derivative of this dot product along

**a**, considering only changes in

**b**.

Ideally, I would like to be able to express this without invoking unit vectors and without || 's, while still using vector notation.