Texas Instuments has developed two devices, the CBR and CBL, that allow one to collect real data and load it direcrtly into the graphing calculator.
Probes explore motion, light, heat, voltage, et ceterea.
A search light is a right angle in the plane. Four search lights are situated at four arbitrary points in the plane. Some generalizations of this problem will be considered at the colloquium talk. Students are encouraged to attend. If you have any comments, suggestions MathWebMaster .