# Tagged Questions

For questions related to the teaching and learning of mathematics. Note that Mathematics Educators Stack Exchange may be a better home for narrowly scoped questions on specific issues in mathematics education.

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### Recommendation for learning math [duplicate]

I'm in the 11th grade. At the bachelor exam, my main focus will be on mathematics and informatics. I'm a hard working man, but due to the school norms, I can consider myself idiot at math. Why? ...
3k views

### How to explain why a parabola opens up or down

I am being ask to explain in 2 ways why is it that y=ax^2+bx+c parabola opens up if a is positive and why is it that y=ax^2+bx+c opens down when a is negative. One of the explanations has to be ...
222 views

### What is the best way to solve this high school exercise?

Can you share with me how would you best solve this exersise to a high school student? Show that $f(x)=x^2-6x+2$ , $x\in(-\infty,3]$ is $1-1$ and find its inverse.
121 views

### How to document undergrad math knowledge?

If you did a degree which is low on math (read economics, psychology), but want to proceed to a more mathematically loaded master, how would you document your knowledge? Are there standarized ...
156 views

### Why to Use the Same Sign for Minus and Negative?

Using the same symbol for two different concepts may cause confusion. So if one decides to do so, they should justify this choice by showing its advantages over other choices. What about the minus ...
131 views

3k views

### Number of Lines Passing Through a Given Point in the Plane

How can one prove that infinite number of lines pass through a given point in plane, using Euclid's axioms (or Hilbert's, if necessary)?
49 views

### On the largest and smallest values of ${D_{\mathbf{u}} f}(x,y)$, assuming that $∇f(x,y) ≠ 0$.

I appreciate your time. If anyone can explain this problem, I would be most grateful. I need to understand this for a test, but I was not given any explanation. Assume that $∇f(x,y) ≠ 0$. Show ...
298 views