"antiderivative" is referenced in the pages listed below.

Given that the general antiderivative of a derivative of a function is just the function plus a constant, We can evaluate integrals where the integrand is one of the derivatives that we already know. Interactive calculus applet.
This applet explores finding the antiderivative graphically, thinking of the integrand as representing the slope of the antiderivative in calculus. Interactive calculus applet.
Not all integrals have antiderivatives that can be written down using the basic functions and operations that we know. Some functions are, in fact, defined using an integral. This page shows two such functions in calculus. Interactive calculus applet.