# NQOTW

## Constructing a Line in a Square

(New Question of the Week) Last month we had a question from a Czech student asking about a geometry problem. The discussion illustrates language issues that can arise, and how we try to guide a student to solve a problem himself. I will fill in some gaps as we examine how to approach an interesting …

## Why is a Linear Equation Called Linear?

(New Question of the Week) From time to time we get a question that is more about words than about math; usually these are about the meaning or origin of mathematical terms. Fortunately, some of us love words as much as we love math. But the question I want to look at here, which came …

## Avoiding “Stupid” Mistakes in Algebra

(New Question of the Week) I like working with a student who is willing to take chances, and also willing to be corrected. As I have often explained, just like a medical doctor, a Math Doctor wants you to “show me where it hurts” in order to diagnose the problem; so showing detailed work is …

(New Question of the Week) One of the strengths of the Math Doctors is the breadth of knowledge represented by our volunteers; we are all different. I have tended here to show the topics that I myself deal with, because those are what I can say most about; but whereas I focus mostly on elementary …

## When Is a Definition Not a Definition?

(New Question of the Week) From time to time a student will ask for help understanding what he reads in his textbook. This often requires some back-and-forth as we try to understand both what the textbook is saying in its context (without having a copy of it to look at), and how the student is …

## Minimizing an Angle

(New Question of the Week) An interesting trigonometry problem came through about a month ago, answered by Doctor Rick. It gives a nice example of how our process works at its best. It is also an interesting problem!

## When Can a Function Equal Its Inverse?

(New Question of the Week) This week I answered a seemingly simple question that can be solved in several different ways when presented as multiple choice, but is rather difficult as a straightforward algebra problem. Trying to guess what the “patient” had done yielded an invalid method that gave the right answer — or was it really invalid? …

## Arrhenius Equation: Which Graph is Right?

(New Question of the Week) Occasionally we get questions challenging the correctness of a textbook problem, or of a test grade. And sometimes we get questions about mathematics used in sciences like physics or chemistry, which lead us to explore unfamiliar fields. The most interesting question this week is one of these. It is one …

## Unfamiliar Geometry Notation

(New Question of the Week) One of the benefits of being a Math Doctor is interacting with the math of many cultures around the world, as we attract an international following. We have observed variations in terminology and notation from country to country, as well as variations in the content of math education (some better …

## Why Do People Treat dy/dx as a Fraction?

(New question of the week) Here is a recent question from Fida, another long-time “patient” of ours at Ask Dr. Math: