Learn more: http://www.khanacademy.org/video?v=K_fgnCJOI8I
Showing that if a vector field is the gradient of a scalar field, then its line integral is path independent

Length: 8 minutes

Closed Curve Line Integrals of Conservative Vector Fields

Length: 11 minutes

Example of Closed Line Integral of Conservative Field

Length: 10 minutes

Second Example of Line Integral of Conservative Vector Field