Second-Order Linear Differential Equations

Author

Miraj Samarakkody

Published

October 26, 2026

This chapter covers equations of the form

\[y'' + p(t)\,y' + q(t)\,y = g(t),\]

which describe mechanical vibrations, electric circuits and many other systems where an acceleration depends on position and velocity. Following Boyce & DiPrima, Elementary Differential Equations and Boundary Value Problems (11th ed., Wiley), Chapter 3, the independent variable is now called \(t\).

Prerequisite: First-Order Differential Equations.

Chapter contents

Section What it covers
3.1 Homogeneous equations with constant coefficients Linear second-order equations, initial value problems, the characteristic equation, distinct real roots, long-term behaviour
3.2 Solutions of linear homogeneous equations; the Wronskian coming soon
3.3 Complex roots of the characteristic equation coming soon
3.4 Repeated roots; reduction of order coming soon
3.5 Nonhomogeneous equations; method of undetermined coefficients coming soon
3.6 Variation of parameters coming soon
3.7 Mechanical and electrical vibrations coming soon
3.8 Forced periodic vibrations coming soon

Numerical methods for second-order equations (rewriting them as first-order systems) are in Numerical Methods, Section 8.