You can check solutions to Differential Equations using WolframAlpha. The slides here illustrate the syntax for first and second order differential equations. Examples like this and more are available from WolframAlpha: Examples for Differential Equations.
Differential Equations on Slideshare.
Notes and examples on Differential Equations.
- CIMT Section 18.5 on First Order Differential Equations
- Units 15.1 to 15.10 from AJ Hobson’s Just the Maths (individual pdf files hosted by UEA) (or a complete pdf from the Math Centre: AJ Hobson’s ‘Just the Maths’) are all on Differential Equations.
- mathcentre: Differential Equations Resources
mathcentre: First Order Differential Equations
mathcentre Second Order Differential Equations - A series of notes from the Helm Project. The complete set is hosted by the Open University. To access the Open University resources you will need to create an account (easy and free), this will also give you access to the numerous free online courses.
Helm Notes – First order ODEs
Mathematics for Students 