Occasionally, I make minor changes to my web lessons, that aren't reflected in my printed books.
In the online lessons, attention is drawn to added material by a purple dashed outline.
Errata are corrected in the online lessons and indicated here.
Such differences between online and printed versions are listed below.
October 29, 2020 Arithmetic and Geometric Sequences Changed 12 to 12.5 (twice) in geometric series example.
October 19, 2020 More on Exterior Angles in Triangles Changed ‘with respect to $\,\angle C\,$’ to ‘with respect to the exterior angle at $\,\angle C\,$’.
October 17, 2020 Practice with Two-Column Proofs Typo (two places): change ‘REASONS columns’ to ‘REASONS column’ (singular).
October 11, 2020 Relationships Between Angles and Sides in Triangles Typo: changed ‘$\,B\Leftarrow A\,$’ to ‘$\,A\Leftarrow B\,$ (that is, $\,B\Rightarrow A\,$)’.
October 11, 2020 Triangle Congruence Changed ‘alternately’ to ‘alternatively’.
October 11, 2020 Angles: Complementary, Supplementary, Vertical, and Linear Pairs Removed the cursor from the vertical angle image.
October 3, 2020 Introduction to the Two-Column Proof Typo: changed ‘in written in’ to ‘is written in’.
October 3, 2020 Proof Techniques Typo: changed ‘the only time than an’ to ‘the only time that an’.
September 28, 2020 Quadrilaterals Changed ‘containing’ to ‘connecting’ in the definition of convex; much clearer.
September 19, 2020 More Practice with Function Notation Missing factor of $\,2\,$ in displayed equation; corrected in online (not print) version.
September 14, 2020 Finding Slant Asymptotes Added a ‘real-life’ example of a slant asymptote to online version, per user request.
September 14, 2020 Finding Vertical Asymptotes Added ‘real-life’ examples of vertical asymptotes to online version, per user request.