Rb-Sr slope: m = e^{λt} − 1; m|_{λt small} ≈ λt; m|_{t = t_{1/2}} = 1

Sympy-exact witness of the Rb-Sr isochron slope formula and its two canonical regime limits. Setup: λ (decay constant) and t (age) declared positive; slope(λ, t) = sp.exp(λ·t) − 1. Three pins: (i) slope_sym = sp.simplify(slope) =…