(25) (25C) Solving 2nd-order differential equations - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: General Software Library (/forum-13.html) +--- Thread: (25) (25C) Solving 2nd-order differential equations (/thread-15354.html) (25) (25C) Solving 2nd-order differential equations - Valentin Albillo - 07-18-2020 05:35 PM   Extracts from HP Program VA251 - HP-25 Solving 2nd-order differential equations Abstract  NUMEROV is a program written in 1975 for the HP-25 / 25C calculators to numerically solve 2nd-order differential equations of the form y”=f(x,y) subject to initial conditions, using the 5th-order predictor-corrector Numerov’s method. One worked example included. Keywords: 2nd-order differential equations, Numerov’s method, HP calculators, HP-25, HP-25C Introduction  NUMEROV is a small (just 37 steps) program that I wrote in 1975 for the HP-25 / HP-25C calculators, which numerically solves 2nd-order differential equations of the form y” = f(x, y), subject to two initial conditions. Notice that y’ doesn’t appear in f’s definition, this is a special case of the more general equation y” = f(x, y, y’). The program uses the 5th-order predictor-corrector Numerov's method, which goes like this:             - predictor: [...] Link to PDF: HP Program VA251 - HP-25 Solving 2nd-order differential equations V.