Differential Equations are the language in which the laws of nature are expressed. Understanding properties of solutions of differential equations is fundamental to much of contemporary science and engineering. Ordinary differential equations (ODE’s) deal with functions of one variable, which can often be thought of as time.
I. First-order differential equations
Miller, Haynes, and Arthur Mattuck. 18.03 Differential Equations, Spring 2010. (Massachusetts Institute of Technology: MIT OpenCourseWare),http://ocw.mit.edu (Accessed 31 Jul, 2012). License: Creative Commons BY-NC-SA