The Department of Mathematics Education
MacTutor History of Mathematics Site  St. Andrew's University
Math Forum (alias Geometry Forum)
Furman University Mathematical Quotation Server
Department
of Mathematics & CS (Georgia College & State University)
Investigating 
Investigating the graph of 
Investigating the pattern of roots as the linear coefficient b changes in the general quadratic

Proving the concurrency of 
GSP Script Tools 
Investigating relationships
between a triangle and 
Tangent Circles 
Ratios, Altitudes and Orthocenters 
Pedal Triangles 
Using parametric equations to generate linear equations 
Investigations with polar equations 
Newton's Law of Cooling 