How Math Errors
What do you do when a book makes an incorrect mathematical statement? Throw the book away? Cross out that statement? Write to the author? etc.
Moore & Mira's The Gist of Mathematics states exponent law: am ÷ an = am-n, then discusses the special case of n = m. They add "therefore, a0 is defined as equal to 1."
But what about the case of a = 0? The authors state "division by zero is excluded. However, many mathematicians define 00 as 1, since this convention introduces more simplification than difficulties."
I wanted to write to the authors for a list of those "many mathematicians," as I am sure L'Hopital would as well.
Unfortunately, Moore and Mira published this book in 1942, so I expect both authors are deceased (e.g. Moore was born in 1884). Thus, their mistake has been read and accepted for the past 70 years...and now lives forever!
Source: J. Moore & J. Mira. The Gist of Mathematics, 1942, p. 31