Closed-form evaluation of the critical-angle formula at the canonical glass–air interface. sin θ_c = n₂/n₁; substituting n₁ = 3/2, n₂ = 1 gives sin²θ_c = (2/3)² = 4/9 (sympy canonical string "4/9"). Corresponds to θ_c = arcsin(2/3) ≈…
Closed-form evaluation of the critical-angle formula at the canonical glass–air interface. sin θ_c = n₂/n₁; substituting n₁ = 3/2, n₂ = 1 gives sin²θ_c = (2/3)² = 4/9 (sympy canonical string "4/9"). Corresponds to θ_c = arcsin(2/3) ≈…