How things change, written as equations and solved three ways — by formula, by picture and by computer: slope fields and first-order equations, oscillators and resonance, the Laplace transform and series, systems, limit cycles, bifurcations and chaos, the solvers every model runs on, the equations of heat, waves, potentials and traffic, and the models of life, money and the planet. Drag every starting point, step every solver and watch every field change on the page.
Every curve, field and number on these pages is computed by the page; your progress stays in this browser. The models of health, money and machines are teaching models and give no medical, financial or engineering advice. Not affiliated with or endorsed by any organisation, publisher or author mentioned here.