Thanks to 1151 student Justin Paro, for his proof of Heron's formula.

Thanks to TA Burhan Biner for maintaining a Home Page for Math 1151,Precalculus II Biner .

Thanks to 1151 student Julia Marasteanu, for finding and correcting a typo, in some copies of Problem 5.2-1 and for her alternate solution to Problem 5.6-35a.