John M Alongi

Recurrence and Topology

Flows Recurrent points Irreducible sets Test functions Afterword Appendix A. Discrete dynamical systems Appendix B. Circle rotations Appendix C. The Hausdorff metric Bibliography Index.

A Geometric Proof of the Addition Identity for Sine.

ABSTRACT We provide a geometric proof of the formula for the sine of the sum of two positive angles whose measures sum to less than π/2. * Thanks to Francesca Fairbrother, Kathy Sheldon and Richard Jurgens for their assistance in preparing this manuscript.

RECOMMENDATIONS ON RECOMMENDATIONS

ABSTRACT Writing letters of recommendations for students is one of the many important duties of a college professor. The letter must accurately portray the experiences and abilities of a student. The recommendation should be positive but truthful — fair to the student, to the person receiving the letter, and to the writer. Here we share some advice for professors on writing a recommendation, present a handout for students seeking recommendations and provide two sample recommendations.