# Errata

This is the errata page for the *Projective Geometric Algebra Illuminated*. To find out which printing you have, look on the copyright page.

## Second Printing

There are no known errata in the second printing. If you have found something, please email the author (lengyel@terathon.com).

## First Printing

**Page 84.**In Table 2.16, both bulk duals of $$\mathbf e_4$$ should be 0. The table should look like the one on the wiki page for duals.

**Page 156.**The number of multiply-adds required for transforming a line with a motor did not include the work needed to calculate $$\mathbf a$$, $$\mathbf b$$, and $$\mathbf c$$. Each cross product adds 6 multiply-adds, so the correct total for transforming a line is 54.

**Page 156.**Similarly, the number of multiply-adds required for transforming a plane with a motor did not include the work needed to calculate $$\mathbf a$$. The correct total for transforming a plane is 35.