Khan/khan-exercises — pull request #11219 by henrikmidtiby (2012-01-14 20:02:25+00:00)
Title: Exercise for calculating eigenvalues of 2x2 matrices.

Related video http://www.khanacademy.org/video/linear-algebra--example-solving-for-the-eigenvalues-of-a-2x2-matrix?playlist=Linear%20Algebra