(93) (εμ - 1)/√(1 - u²) (W ∂u/∂xh),
The round bracket denoting the scalar product of the vectors within it.
§ 14. The Ponderomotive Force.[[28]]
Let us now write out the relation K = lor S = -sF + N in a more practical form; we have the four equations
(94) K₁ = ∂Xx/∂x + ∂Xy/∂y + ∂Xy/∂z - ∂Xt/∂t = ρEx + syMz - szMx
- ½ Φ[=Φ] ∂ε/∂x - ½ ψ[=ψ]∂μ/∂x + (εμ - 1)/√(1 - u²) (W∂u/∂x),
(95) K₂ = ∂Yx/∂x + ∂Yy/∂y + ∂Yz/∂z - ∂Yt/∂t = ρEy + szMx - sxMy
- ½ Φ[=Φ]∂ε/∂y - ½ ψ[=ψ]∂μ/∂y + (εμ - 1)/√(1 - u²) (W∂u/∂y),
(96) K₃ = ∂Zx/∂x + ∂Zy/∂y + ∂Zz/∂z - ∂Zt/∂t = ρE₂ + sxMy - syM₄
- ½ Φ[=Φ] ∂ε/∂z - ½ ψ[=ψ] ∂μ/∂z + (εμ - 1)/√(1 - u²) (W∂u/∂z),