# 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.

1answer
23 views

### Question about a g-force simulator in question 6, part b, regarding the moments in a balanced system at rest.

The following is regarding question $6$, part $b$, in the following link: https://thol.sunway.edu.my/examdbase/alv/math/p3/math_p3_j96.pdf Using the principle of moments and considering the case ...
0answers
22 views

### Notation for points in 2d or 3d coordinate systems P(a|b|c)? Origin and reasons?

In every german high school book about vector geometry, points in 2d or 3d cartesian coordinate systems are denoted like $P(2|-1|5)$. Very rarely one also reads something like $P = P(2|-1|5)$. But I ...
1answer
54 views

### How do I find a percentage with only the mean and standard deviation?

'If we have a set of scores that are normally distributed and have a mean of 20 and a standard deviation of 5, what percentage of scores are greater than 20?' Now I know the answer is 50%, because ...
2answers
30 views

### Query on previous post regarding the distance formula for perpendicular lines and negative slopes made 2 years ago.

In the post made 2 yrs ago 'Explain why perpendicular lines have negative slopes', Explain why perpendicular lines have negative reciprocal slopes How does the distance formula get applied to obtain ...
3answers
46 views

### Suggestions on Progressing in (Meta)Mathematical Development [closed]

[Straight to the Point] I would really appreciate any suggestions on self-study materials that relate to math, logic, and/or the philosophy of both. Also, any thoughts or suggestions that you may ...
4answers
428 views

### Map closed under addition but not multiplication

I have been helping undergrads in an introduction to linear algebra course. When solving some exercise consisting in showing that a map is linear some get lazy after proving that it is closed under ...
0answers
36 views

### Can I get some help to make my answer more rigorous for this problem in the book Concrete Mathematics [duplicate]

I'm a freshman in college this semester without any previous experience in rigorous proofs or such, however I am interested in the learning more about mathematics and for that reason I picked up the ...
2answers
90 views

### What topics should be included in a course matching these specifications?

Say you have a calculus classroom full of liberal-arts majors who are not particularly mathematically inclined. Your goal is NOT to teach them everything on a list of topics that will be needed in ...
0answers
17 views

### Can sombody give me an ntuitive explanation about regression estimates as weighted averages?

I am trying to study weighted least square and found one article that sounds like it is explaining what I am trying to study. But I want to get some intuitive explanation about each calculation and ...
0answers
15 views

### Percentage Calculation - Cells per micro litre

I came across this simple percentage calculation and I couldn't solve it (I couldn't prove otherwise). Here's the problem. Find percentage for 11/0.1 ul (11 cells per 0.1 micro litre). Any pointers ...
2answers
36 views

### Prove that $|x − y| < \epsilon$ , $|y − z| < \epsilon$ implies $|x-z|<2\epsilon$

I need the math.triangle inequality formula, but I still didn't get it fully. be die|x|+|y| <= |x+y| |x|+|y| <= |x+y| I put in the values |x-y| < ε <= |x|-|y| < ε |y-z| < ε ...
0answers
33 views

### How can I explain a Zero Knowledge Proof with minimal mathematics

I asked this earlier on how to explain a Zero Knowledge Proof to a layman. but I'm looking for a mathematical analogy that might "enhance" the superpower explanation. In that linked superpower, that ...
0answers
147 views

### I have a free summer before university. What should I learn? [closed]

Note: This is a soft question. It may be a bit early to be thinking about this, but I figured I'd ask now and see what responses I get. I'm currently a high school senior, and I quite like pure ...
0answers
90 views

### Calculus as a structure in the sense of Model theory

I am not a specialist in Logic (my field is Functional Analysis), so excuse me my ignorance. I suppose there must be texts where Calculus is presented as a structure in the sense of Model theory. I ...
0answers
52 views

1answer
28 views

### A “Simple Chain of Regions” and Compactness in the Continuum

Let me just start by saying that I'm basically trying to prove this: How to prove every closed interval in R is compact? Except that I need to do it in a very strange way... I'm teaching an Inquiry-...
1answer
84 views

### Visual questions for 6th graders

I'm tutoring a 6th grader in math at the moment and because she never has a ton of homework I like to give her some interesting extra problems to do. It seems she really enjoyed a problem I showed ...
1answer
20 views

2answers
34 views

### How to convert linear programming model to standard form?

This might be a stupid question. For that, I'm truly sorry. But I appreciate any help!
1answer
53 views

### find the derivative of (cosx)^(sinx)^x

Solve to find the derivative of the following function: (cosx)(sinx)x Do not simplify the answer.
2answers
36 views

### How to convert mathematical program into an LP?

This might be a stupid question. For that, I'm truly sorry. But I appreciate any help! minimize (max {2x-4, |x|}) subject to -3 <= x <= 6
2answers
98 views

### Showing that $\cos (\sqrt x)=e^x-2$ has solution in $(0,1)$

I rephrased this problem as finding a solution of $f(x)=e^x-2-\cos(\sqrt x)$ in $(0,1)$. I apply the intermediate value theorem: $f(0)=e^0-2-\cos0=-2$. The goal is to show $f(1)>0$ (which is true) ...
0answers
30 views

### Function satisfing : $h(x)=f(2x-1)$ with $f'(-1)=0$ and $f'(2)=-2$ then what is $h'(x)$?

I find in some book this function defined as follow $h(x)=f(2x-1)$ . with $f'(2)=-2$ and $f'(-1)=0$ , we would like to know $h'(3/2)$ ? In the book take $h'(x)=f'(2x-1)=(f'(2))x+f'(-1)=-2x$ but ...
0answers
31 views

### Powerful pictures or plain proceedings?

After tutoring someone about polynomial manipulation, my mind went back to this equivalence: $(a+b)\times (c+d)=ac+ad+bc+bd$ I realized that, while it can be memorized as it is, it has a very simple ...
2answers
230 views

### What is the right way to define a function?

Most authors define functions this way: Given the sets $A$ and $B$. A relation is a subset of $A\times B$. Then given a relation $R$, we define $Dom_R=\{x|(x,y)\in R\}$ and $Img_R=\{x|(y,x)\in R\}$. ...
3answers
133 views

1answer
56 views

### For an introductory analysis class, why is it that many people avoid teaching it using sequences?

I am currently taking an honors introduction to analysis course, and it seems to me that to me defining all of the concepts in terms of sequences allows for much cleaner proofs, and the concepts are ...
1answer
64 views

### Variation on the “Number of non-bald people in NYC” problem

I have two questions about the following problem, taken from Challenging Problems in Algebra by Posamentier and Salkind: (1) Why is the answer not 1 person? (2) The answer given, without solution, is ...