- #1

- 3

- 0

## Main Question or Discussion Point

**reading Smythe's book on "static and dynamic electricity"**

Hi,

I am reading Smythe's book on "static and dynamic electricity" (1st edition, 1939) and I'm having trouble deriving some of the formulas. I wonder if someone already corrected that. For instance,

1.10 - Gauss's electric flux theorem. The expression for the normal flux component has a superfluous K : [tex] dN = E_n \cdot dS[/tex]

1.101 - I can't seem to obtain the expression for N, unless if [tex]sin^2(\alpha) = 2 \cdot (1 - cos(\alpha))[/tex] (actually : [tex] 1- cos(2\alpha) = 2 \cdot sin^2(\alpha)[/tex]).

thanks,

Nakis