# Math Help - Testing LaTeX 2

1. Originally Posted by Jones
Hehe, how would i get a left bracket first to indicate an equation system, (or congruence system if you like)
Try this :

$\begin{cases}
\phi(n) \equiv q \pmod{42} \\
p \equiv n \pmod{234^{432}} \\
\end{cases}$

If you want to have the symbols $\equiv$ aligned you can use the command & :

$\begin{cases}
\phi(n) & \equiv q \pmod{42} \\
p & \equiv n \pmod{234^{432}} \\
\end{cases}$

If you don't want $q$ and $\phi(n)$ to be aligned on the left, you'll have to use an array instead of the cases environment :

$
\left\{
\begin{array}{ccl}
\phi(n) & \equiv & q \pmod{42} \\
p & \equiv & n \pmod{234^{432}} \\
\end{array}
\right.
$

$
\left\{
\begin{array}{rcl}
\phi(n) & \equiv & q \pmod{42} \\
p & \equiv & n \pmod{234^{432}} \\
\end{array}
\right.
$

2. ## Arc symbol

What do you use for the arc symbol? I've been using

\widehat{ABC} to get $\widehat{ABC}$, but that's not quite it.

I tried using: \stackrel{\frown}{ABC}

$\stackrel{\frown}{ABC}$

That just doesn't look right, either. It's too small.

3. Originally Posted by masters
What do you use for the arc symbol? I've been using

\widehat{ABC} to get $\widehat{ABC}$, but that's not quite it.

I tried using: \stackrel{\frown}{ABC}

$\stackrel{\frown}{ABC}$

That just doesn't look right, either. It's too small.
You can make it slightly bigger by \stackrel{\textstyle\frown}{ABC}:

$\stackrel{\textstyle\frown}{ABC}$

4. Originally Posted by Opalg
You can make it slightly bigger by \stackrel{\textstyle\frown}{ABC}:

$\stackrel{\textstyle\frown}{ABC}$
Yeah, that'd be ok for minor arcs like $\stackrel{\textstyle\frown}{AB}$

5. Let $X$ be a metric space, and let $E\subset{X}$. Now define $S\equiv\left\{d(p,q):q,p\in{E}\right\}$, now if $\sup\left(S\right)=\gamma$ we may equivalently write $\diam\left(E\right)=\gamma$...Is ther a code that gives $\text{diam}\left(E\right)$?

6. Originally Posted by Mathstud28
Let $X$ be a metric space, and let $E\subset{X}$. Now define $S\equiv\left\{d(p,q):q,p\in{E}\right\}$, now if $\sup\left(S\right)=\gamma$ we may equivalently write $\diam\left(E\right)=\gamma$...Is ther a code that gives $\text{diam}\left(E\right)$?
From what I know, no. One can define this command...but you can't do so here on MHF. If you had a LaTeX editor [like TeXnic Center], you can post the following into the preamble of the document:

Code:
\newcommand{\diam}[1]{\text{diam}\left(#1\right)}
And then when you type \diam E, it gives you $\text{diam}\left(E\right)$

--Chris

7. Originally Posted by Chris L T521
From what I know, no. One can define this command...but you can't do so here on MHF. If you had a LaTeX editor [like TeXnic Center], you can post the following into the preamble of the document:

Code:
\newcommand{\diam}[1]{\text{diam}\left(#1\right)}
And then when you type \diam E, it gives you $\text{diam}\left(E\right)$

--Chris
Haha, that is a lot of work. I think I will just stick with $\text{diam}\left(E\right)$

Thanks though!

8. $\begin{pmatrix}
a_{1,1} & a_{2,1} & \ldots & a_{n,1}\\
a_{2,1} & a_{2,2} & \ldots & a_{n,2}\\
\hdotsfor[1.7]{4}\\
a_{n,1} & a_{2,n} & \ldots & a_{n,n}
\end{pmatrix}$

$\begin{pmatrix}
a_{1,1} & a_{2,1} & \ldots & a_{n,1}\\
a_{2,1} & a_{2,2} & \ldots & a_{n,2}\\
\vdots & \vdots & \ddots & \vdots \\
a_{n,1} & a_{2,n} & \ldots & a_{n,n}
\end{pmatrix}$

9. $
\begin{matrix}0&1\\1&0\end{matrix} \hspace{1.5pc}
\begin{pmatrix}0&1\\1&0\end{pmatrix} \hspace{1.5pc}
\begin{bmatrix}0&1\\1&0\end{bmatrix} \hspace{1.5pc}
\begin{Bmatrix}0&1\\1&0\end{Bmatrix} \hspace{1.5pc}
\begin{vmatrix}0&1\\1&0\end{vmatrix} \hspace{1.5pc}
\begin{Vmatrix}0&1\\1&0\end{Vmatrix}

$

10. $\sum_{k=0}^n$

$\sum_{k=0}^n a^k$

$\sum_{r=0}^n a^r$

$
\sum_{r=0}^n\ ^nC_r a^r$

$\sum_{r=0}^n ^nC_r a^rb^{n-r}$

$(x+y)^n$

$$$x+y$$^n$

11. $
-e^{-x^2}
$

equals 0

12. $\int\limits_-\cdots \int\limits_\text{ }^-\cdots\int\limits_a^b$

Math $\int\limits_- f~d\alpha=\sup_{P}L\left(P,f,\alpha\right)$

13. . . . $\frac{1{\color{red}\rlap{/}}6}{{\color{red}\rlap{/}}64} \;=\;\frac{1}{4} \qquad\qquad \frac{1{\color{red}\rlap{/}}9}{{\color{red}\rlap{/}}95} \;=\;\frac{1}{5}$ . . . . . $\frac{2{\color{red}\rlap{/}}6}{{\color{red}\rlap{/}}65} \;=\;\frac{2}{5}\qquad\qquad \frac{4{\color{red}\rlap{/}}9}{{\color{red}\rlap{/}}98} \;=\;\frac{4}{8}\;=\;\frac{1}{2}$

. . . . . $\frac{1-x^{{\color{red}\rlap{/}}2}}{(1+x)^{{\color{red}\rlap{/}} 2} }\;=\;\frac{1-x}{1+x}$

All that work for a bad joke . . .

(Good luck trying to read my LaTeX code.)
.

14. A fairly comprehensive guide to LaTeX here:

http://tobi.oetiker.ch/lshort/lshort.pdf

15. Just trying something fancy in LaTex. This came from that tutorial.

$\text{Heron's formula}\setlength{\unitlength}{1cm}
\begin{picture}(6,5)
\thicklines
\put(1,0.5){\line(2,1){3}}
\put(4,2){\line(-2,1){2}}
\put(2,3){\line(-2,-5){1}}
\put(0.7,0.3){A}
\put(4.05,1.9){B}
\put(1.7,2.95){C}
\put(3.1,2.5){a}
\put(1.3,1.7){b}
\put(2.5,1.05){c}
\put(0.3,4){F=
\sqrt{s(s-a)(s-b)(s-c)}}
\put(3.5,0.4){\displaystyle
s:=\frac{a+b+c}{2}}
\end{picture}$

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