(25) (25C) Solving 2nd-order differential equations

[Valentin Albillo]

 
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

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