Problem 3.371

A point charge $q$ moves uniformly and rectilinearly with a relativistic velocity equal to a $\beta$ fraction of the velocity of light $(\beta=v / c) .$ Find the electric field strength $\mathbf{E}$ produced by the charge at the point whose radius vector relative to the charge is equal to $\mathbf{r}$ and forms an angle $\theta$ with its velocity vector.