David Joyner and Marshall Hampton's lucid textbook explains differential equations using the free and open-source mathematical software Sage. Since its release in 2005, Sage has acquired a substantial following among mathematicians, but its first user was Joyner, who is credited with helping famed mathematician William Stein turn the program into a usable and popular choice. Introduction to Differential Equations Using Sage extends Stein's work by creating a classroom tool that allows both differential equations and Sage to be taught concurrently. It's a creative and forward-thinking approach to math instruction. Topics include: * First-Order Differential Equations * Incorporation of Newtonian Mechanics* Second-Order Differential Equations* The Annihilator Method* Using Linear Algebra with Differential Equations* Nonlinear Systems* Partial Differential Equations* Romeo and Juliet