Langmuir: θ(Kp = 1) = 1/2 (half-coverage); dθ/dp|_{p=0} = K (Henry slope)

Sympy-exact symbolic witness of the Langmuir half-coverage anchor and Henry-law limit. Setup: θ(p) = K·p/(1 + K·p) with K, p positive symbols. Canonical form (sympy Mul-expanded): θ_sym = 'K*p/(K*p + 1)' — the rectangular-hyperbolic…