(New question of the week) Now that we are receiving questions at the new site, we will be periodically posting some of those questions and answers, in addition to going back to particularly interesting questions from the old archive. This question (which I have slightly edited) came to The Math Doctors earlier this month, from …
Why Must the Number of Variables Equal the Number of Equations? Read More »
(Archive question of the week) One day back in November, as I entered the community college where I teach, a man came in behind me with his son, probably about 3 years old. It was the first snowy day of the year, and the father stood on the mat wiping his feet, while the little …
While pondering issues that often give students trouble in algebra, I decided to check what we have said in Ask Dr. Math about inverse functions. I discovered four answers (all, as it happens, written by me – I tend to be attracted to certain topics!) to essentially the same question, spread over 13 years. It …
How to Find an Inverse Function: Conflicting Approaches Read More »
Last time, I talked about students’ difficulties carrying out divisions that involve a zero, which reminded me of another issue that sounds almost the same, but is quite different: division of a number by zero. Students often either forget the rule they were taught, or they don’t believe the rule, or they just wonder about …
In its more than 20 years, we answered hundreds of thousands of questions on Ask Dr. Math, only a small fraction of which were archived for public access. Those that did not make it into the archive were not bad answers, just not deemed to be of broad enough interest, or unique enough, to be …
A Sample of Ask Dr. Math, Part 1: Questions from School Read More »