Texas Instruments
Texas Instruments: Applications of Integrals
Use the TI-89 to find the area between curves, find arc length, and solve first and second order differential equations. Examples in the activity use calculator screenprints and keystroke instructions to demonstrate the use of the...
Wolfram Research
Wolfram Math World: First Order Ordinary Differential Equation
This math site defines a first order differential equation. Includes information on how to solve an equation of this form and also how to find the roots.