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# Quick LaTeX Tutorial

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Help! How do you compose the vertical line evaluating an integral at limits?

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Use a left,right pair where the left element is invisible: \left.\frac F G \right|^R_1

$\left.\frac F G \right|^R_1$

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Thanks, D H, I would not have figured that out.

Also, I didn't know you need not give brackets after \frac , as the space delineates the argument change. Correct?

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Correct. \frac takes two arguments. You only need to use the brackets if an argument is non-atomic. You don't even need the space if you use brackets. The space exists to separate arguments. It does not print. You can even take advantage of the fact the digits cannot be part of a name and hence separate arguments without a space. For example \frac1a, which displays as $\frac1a$. Nontheless it's a good practice to use the braces even when they aren't needed.

One problem with the way LaTeX treats spaces is if when you define a macro (in a .tex or .sty file, not here) that prints something. For example suppose you define \mbsp as shorthand for "My Big Software Package version 3.1":

\newcommand{\mbsp}{My Big Software Package version 3.1}

Now you can brag about a specific version of your big software package with \mbsp:

The following capabilities are now available in \mbsb:\begin{itemize}\item Feature 1 ...

This will work fine:

The following capabilities are now available in My Big Software Package version 3.1:
• Feature 1 ...

Now someone redlines this as passive voice. You change it to

\mbsb offers the following capabilities:\begin{itemize}\item Feature 1 ...

But this prints as

My Big Software Package version 3.1offers the following capabilities:
• Feature 1 ...

There is no space between 3.1 and offers. You need to force the space, for example

\mbsb\ offers the following capabilities:\begin{itemize}\item Feature 1 ...

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D H, Cool and thank you. [bIGTEETH]

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is there a better way to test this or practice than trial and error?

$c=2\pi*r*\cos\Theta$

Edited by honestdude14
multiple post merged

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Not really. You can use the Preview Post feature and try it as many times as you'd like though.

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$\text{this is a test}$

fine, it works

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$\displaystyle\int_0^{\infty} (Air) \ \mathrm{d}x$

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What's the code for complex conjugate, you know, something "star"?

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$x^*$ ? Just use x^* or x^{*}.

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I am working in OpenOffice and this didn't cut it. It's looking for a multiplicand.

Merged post follows:

Consecutive posts merged

I got into the OpenOffice forum and the answer is: "*" in the superscript.

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Perhaps more to the point, which symbol is used more these days for c.c., the asterisk or a bar-over?

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Perhaps more to the point, which symbol is used more these days for c.c., the asterisk or a bar-over?

Complex conjugate?

I have seen both used, provided the one you pick is not also being used for something else you will be alright.

I think bar is in common usage in complex geometry. If you are more of an algebraist you may prefer to use the star as it resembles the adjoint in *-algebras.

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Thanks, ajb. I work in the zone between geometry and algebra, between knowledge and imagination, light and dark. Do not try to adjust your monitor...

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Is there any provision for drawing commutative diagrams? Something like Paul Taylor's "diagrams".

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We used to have a [diag] tag that used diagxy for diagrams. I'm not sure why it's no longer available. Perhaps I can hack it back in sometime, unless Dave removed it for a particular reason.

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Only some of the logic notation appears to work:

All rendering okay:

[imath]\forall p \exists q[/imath], [imath]p \therefore q[/imath], [imath]p=\not q[/imath], [imath]p \neg q[/imath].

Not rendering:

[imath]p \and q [/imath], [imath]p \or q [/imath].

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\and and \or aren't symbols in LaTeX. You can use \wedge and \vee though.

$p \wedge q$, $p \vee q$

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Strange, they appear on the Wikipedia LaTeX guide - maybe they are using an obscure package.

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I think Wikipedia uses a bunch of the AMS packages by default. I could add some to our package list if you find out what we need.

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One thing that hasn’t been mentioned in this thread so far is formatting colors in LaTeX.

$\color{red}{\rm red}$

$\color{blue}{\rm blue}$

$\color{green}{\rm green}$

$\color{yellow}{\rm yellow}$

$\color{black}{\rm black}$

$\color{white}{\rm white}$

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I have learned LaTeX because in my college i have to write reports and papers in LaTeX,

test:

$|x| = \{ \begin{matrix} \color{red}{-X}&\color{red}{if X<0}\\ \color{blue}{X}&\color{blue}{if X>0}\\ \end{matrix}$

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I have learned LaTeX because in my college i have to write reports and papers in LaTeX,

test: $|x| = \{ \begin{matrix} \color{red}{-X}&\color{red}{if X<0}\\ \color{blue}{X}&\color{blue}{if X>0}\\ \end{matrix}$

In that case you might want to use \mbox around plain text such as 'if', and use the \cases notation rather than trying to hack your way around a matrix.

$f(x) = \begin{cases} \ln(1-x) & \mbox{if} \; x<0 \\ 1 & \mbox{if} \; 0\leq x < c \\ x^2 & \mbox{otherwise} \end{cases}$

See how that looks neater both in terms of code and output?

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Why doesn't the factorial sign work in LaTex here? for example, $\frac{1}{2}$ works, but when I use factorial sign after the '2' in the denominator, I get an error message: $\frac{1}{2!}$

.

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