Show that the scalar potential of a point charge moving with constant velocity (Eq. 10.4...

Show that the scalar potential of a point charge moving with constant velocity (Eq. 10.49) can be written more simply as

where R ≡ r − vt is the vector from the present (!) position of the particle to the field point r, and θ is the angle between R and v (Fig. 10.9). Note that for nonrelativistic velocities (v² ≫ c²),

Equation 10.49