Theorem (Fresnel-normal-incidence-residual canonical): R = r^2 = ((n_1 - n_2)/(n_1 + n_2))^2 cleared of denominators gives R (n_1 + n_2)^2 = (n_1 - n_2)^2, hence R (n_1 + n_2)^2 - (n_1 - n_2)^2 = 0 identically. Canonical sympy pins: n1, n2…
Theorem (Fresnel-normal-incidence-residual canonical): R = r^2 = ((n_1 - n_2)/(n_1 + n_2))^2 cleared of denominators gives R (n_1 + n_2)^2 = (n_1 - n_2)^2, hence R (n_1 + n_2)^2 - (n_1 - n_2)^2 = 0 identically. Canonical sympy pins: n1, n2…