WolframAlpha can be used to check calculus examples, see the examples within this Slideshow
WolframAlpha Examples part 4
Integration Applets, including this Numerical Integration Utility
Numerical Integration Utility – Zweigmedia
Try Calculus Applets for a comprehensive collection of Calculus Applets using GeoGebra, a project by Marc Renault, supported by Shippensburg University.
Can you draw a graph of the derivative function?
Mathematics for Students 