Thanks to the generous person who submitted the following error in the ebook.
It is in the section on mathematical operations on complex numbers.
In the book (a + bi) + (c + di) = (a + b) + (c + d)i
Should be (a + bi) + (c + di) = (a + c) + (b + d)i
In the book (a + bi) – (c + di) = (a - b) + (c - d)i
Should be (a + bi) – (c + di) = (a - c) + (b - d)i
I'll update the ebook asap and you should be able to request Amazon Kindle to get an updated version at no extra cost. I understand the updates aren't always automatically pushed out by Amazon.
UPDATE: Amazon Kindle ebook is now updated with this correction.