Reading Smythe's book on static and dynamic electricity

Nakis
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 : $$dN = E_n \cdot dS$$
1.101 - I can't seem to obtain the expression for N, unless if $$sin^2(\alpha) = 2 \cdot (1 - cos(\alpha))$$ (actually : $$1- cos(2\alpha) = 2 \cdot sin^2(\alpha)$$).

thanks,

Nakis

Homework Helper
Gold Member
I suggest you try a newer high level EM book with clearer derivations than Smythe.
No trig is needed to derive Gauss's law.

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