Physics and Python stuff. Most of the videos here are either adapted from class lectures or solving physics problems. I really like to use numerical calculations without all the fancy programming ...

Grade school math students are likely familiar with teachers admonishing them not to just guess the answer to a problem. But a new proof establishes that, in fact, the right kind of guessing is ...

SIAM Journal on Applied Mathematics, Vol. 31, No. 4 (Dec., 1976), pp. 579-585 (7 pages) Necessary and sufficient conditions for existence and expressions for general Hermitian and nonnegative definite ...