Monthly Archives: August 2012

The Integral of Secant

My first question on math.SE asked for different ways to evaluate .  This post will discuss my original method for evaluating , the method in my favorite answer from the math.SE question, and why the two are equivalent (even though they … Continue reading

Posted in calculus | Leave a comment

When Do 2×2 Covariance Matrices Have Repeated Eigenvalues?

The calculation answering the question in the title is not that difficult, but I needed it recently, and so I thought I would add it to my blog. Suppose we have a covariance matrix By definition, the eigenvalues are the … Continue reading

Posted in linear algebra, matrices | 2 Comments