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Questions tagged [reflection]

Reflection is a transformation that fixes a line or plane or a more general subset. Reflections appear in geometry, linear algebra, complex analysis, differential equations, etc -- therefore, this tag must be used with a tag describing the area of mathematics.

3 votes
1 answer
56 views

If given a point $(x,y)$, and told to reflect it across a given line $y=mx+b$, there are several ways that this can be achieved. For one, the most simple way is to just count the diagonals, but this ...
Person12343's user avatar
1 vote
1 answer
78 views

I'm trying to understand to Wythoffian constructions. In particular, how to show that when additional mirror is activated, all the previous faces remain (translated and dilated) and are separated by ...
user145836's user avatar
2 votes
2 answers
82 views

From a previous post, the following fact has been brought to my attention: For any two continuous functions $f, g: \mathbb{R} \rightarrow \mathbb{R}$, the following function is an isotopy of $\mathbb{...
Robert Abramovic's user avatar
2 votes
2 answers
134 views

A straight line with a negative slope passes through the point $P(8,1)$ and meets x-axis at $A$ and the y-axis at $B$. Find the minimum possible value of the perimeter of $\triangle AOB$. My Attempt ...
Maverick's user avatar
  • 11.2k
0 votes
1 answer
42 views

Let $A$ be a subset of $\mathbb{R}$ and let $f: A \rightarrow \mathbb{R}$ be a continuous function. If $f(x) = mx$ for some positive number $m > 0$, then the function $H: \mathbb{R}^{2} \times [0, ...
Robert Abramovic's user avatar
0 votes
1 answer
33 views

Suppose $\mathbf{s}=(s_1,\dots,s_k)$ is a word in $S$. Define $w_i\in W$ by $w_0=1$ and $w_i=s_1\cdots s_i$, and $r_i\in R$ by $r_i=w_{i-1}s_iw_{i-1}^{-1}$. Set $\Phi(\mathbf{s}):=(r_1,\dots,r_k)$. ...
itkyitfbku's user avatar
0 votes
0 answers
31 views

$\DeclareMathOperator\PSU{PSU}\DeclareMathOperator\U{U}\DeclareMathOperator\SU{SU}\DeclareMathOperator\O{O}\DeclareMathOperator\SO{SO}\DeclareMathOperator\GL{GL}\DeclareMathOperator\ASL{ASL}\...
Ian Gershon Teixeira's user avatar
2 votes
1 answer
158 views

I was able to find the following formula when reflecting a point $(x,y)$ to point $(x^\prime,y^\prime)$ over the line $y = mx$: $$(x^\prime,y^\prime)=\left(\frac{1-m^2}{1+m^2}x+\frac{2m}{1+m^2}y,\frac{...
Nate's user avatar
  • 313
1 vote
0 answers
39 views

Let two mirror surfaces be defined by the graphs of functions $y=\frac{1}{x}$ and $y=-\frac{1}{x}$ for all $x>0$. A beam of light originates at the point $(0, a)$ $(a>0)$ and travels ...
lithus eric's user avatar
0 votes
1 answer
58 views

Is there a standard mapping notation for rotations and reflections? Some sources I've looked at use R for rotations and r for reflections, others don't really make a distinction and may use the same ...
Nate's user avatar
  • 313
3 votes
1 answer
185 views

Suppose I have a finite set $S$ in $\mathbb{R}^n$ and reflections $\sigma_j$ defines as follow:$$\sigma_ j x=\sigma_j(x_1,\ldots,x_{n})=(x_1,\ldots,-x_j,\ldots,x_{n})$$ Formerly, I tried to decompose $...
user avatar
0 votes
1 answer
58 views

Translations are easy in Cartesian coordinates since each point P can be moved to its corresponding point P$^\prime$ with either a 2-component vector on the plane or a 3-component vector in space. ...
Nate's user avatar
  • 313
0 votes
1 answer
289 views

As shown in the diagram, a laser light originates vertically from point $A$ and must reach point $T$. There are two rotating mirrors that adjust their angles based on a given relationship with $\theta$...
Incompleteness's user avatar
0 votes
1 answer
44 views

To the best of my knowledge, if $R$ is a (reduced) irreducible root system in some real vector space $V$, then its Weyl group $W(R)$ is the finite Coxeter group generated by the reflections associated ...
Curious's user avatar
2 votes
0 answers
121 views

I am reading "Reflecting Barriers" related chapters in Cox and Miller's book "The theory of stochastic processes". On page 224 it says that: $"$ Consider a Wiener process $X(t)$ ...
Stephen Ge's user avatar

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