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Quick Guide to Maths Symbols on the computer

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#1 Sandwich Posted Jun 08, 2011 - 11:11

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IBS has a system set up which allows you to enter in various bits of code and have them appear as mathematical symbols called Tex tags. For instance, rather than writing x^3, you can write $x^3$. This is a quick guide explaining how to make this work for some of the more common Maths symbols you need for the IB.
It may also come in handy as a way to copy/paste in as graphics for IAs, where relevant.
For a more comprehensive overview, please take a look at this site: http://en.wikibooks....TeX/Mathematics

Additional Links (kindly suggested by Chrypton)
Detexify - This site contains a white drawing area where you can draw a math symbol that you don't know the LaTeX code for. Very helpful.
AoPS LaTeX Guide - A comprehensive guide to using LaTeX. It also shows you how to create good-looking LaTeX documents.

Also thanks to Ezeh for suggesting some of the symbols on this list.

Skip to:
1 Activating the Code
2 Indices
3 Fractions
4 Binomials and Vectors
5 Square Root
6 Integration & Differentiation
7 Matrices
8 Greek Symbols
9 Trigonometry (sin, cos etc.)
10 Sums & Limits
11 Miscellaneous Symbols

1 Activating the Code

To do this, you need to enter whatever piece of Maths you're doing in using Tex tags. You can either type these in directly - [ tex ] content [ /tex ] (without the spaces) OR you can select it from the list shown in the top left of your reply box. Where it says "Other Styles", click and scroll down until you find Tex.

2 Indices

$x^7$
Achieved by: x^7

$x^{-7}$
Achieved by: x^{-7}
(To include the negative sign in negative indices please enclose it in squiggly brackets { and })

3 Fractions

${n \over k(n-k)}$
Achieved by: {n \over k(n-k)}

4 Binomials & Vectors

${n \choose k}$
Achieved by: {n \choose k}

5 Square Root

$\sqrt{\frac{a}{b}}$
Achieved by: \sqrt{\frac{a}{b}}

OR

$\sqrt[n]{1+x+x^2+x^3+\ldots}$
Achieved by: \sqrt[n]{1+x+x^2+x^3+\ldots}

6 Integration & Differentiation

$\int\limits_a^b$
Achieved by: \int\limits_a^b

$\frac{du}{dt}$
Achieved by: \frac{du}{dt}

$\int_0^\infty e^{-x}\,\mathrm{d}x$
Achieved by: \int_0^\infty e^{-x}\,\mathrm{d}x

7 Matrices

$A_{m,n} = \begin{pmatrix} a_{1,1} & a_{1,2} & \cdots & a_{1,n} \\ a_{2,1} & a_{2,2} & \cdots & a_{2,n} \\ \vdots & \vdots & \ddots & \vdots \\ a_{m,1} & a_{m,2} & \cdots & a_{m,n} \end{pmatrix}$

Achieved by: A_{m,n} = \begin{pmatrix} a_{1,1} & a_{1,2} & \cdots & a_{1,n} \\ a_{2,1} & a_{2,2} & \cdots & a_{2,n} \\ \vdots & \vdots & \ddots & \vdots \\ a_{m,1} & a_{m,2} & \cdots & a_{m,n} \end{pmatrix}

Just to sum this one up, basically you start a matrix using the code
\begin{pmatrix}

You then enter in the terms horizontally, so along the line, using & to indicate the next term e.g.
{1,1} & {1,2} & {1,3}

Please note that if you wish to enter anything into the matrix which is more than just a letter (e.g. a, b, c) or number (e.g. 1, 5, 10 etc.) such as coordinates which have a comma in the middle (i.e. 1,2 2,2, 3,2 etc.) then you need to enclose those inside these squiggly brackets { and } in order for them to come out properly. So {1,2}, {2,2}, {3,2} as in the example above. This is also true for negative numbers. Basically you can think of it as the squiggly brackets indicating to your browser that all symbols within a term belong together.

To indicate that you require a new line in the matrix, use a double backwards slash - \\

Use \end{pmatrix} to close the matrix.

To put all this together, say I wanted a 3 x 3 Matrix with a, b, c // d, e, f // g, h, i...
I would put in: \begin{pmatrix} a & b & c \\ d & e & f \\ g & h & i \end{pmatrix}

$\begin{pmatrix} a & b & c \\ d & e & f \\ g & h & i \end{pmatrix}$

8Greek Symbols

$\theta \epsilon \alpha \beta \kappa \lambda \delta \mu \pi \sigma \tau \omega$

Achieved by: \theta \epsilon \alpha \beta \kappa \lambda \delta \mu \pi \sigma \tau \omega

Literally a backwards slash followed by the name of the symbol you desire. Note that if you spell the symbol with a capital letter (e.g. \Beta) you will get the capital version B as opposed to spelling it with lowercase (\beta) in which case you get $\beta$, the lower case version.

9 Trigonometry
$\cos (2\theta) = \cos^2 \theta - \sin^2 \theta$
Achieved by: \cos (2\theta) = \cos^2 \theta - \sin^2 \theta

In other words, $\cos \sin$ and $\tan$ can be achieved using \cos \sin \tan

10 Sums & Limits
$\sum_{i=1}^{10} t_i$
Achieved by: \sum_{i=1}^{10} t_i
Where i is the number at the bottom and the top number is the 10.

$\lim_{x \to +\infty}$
Achieved by: \lim_{x \to +\infty}

11 Miscellaneous Symbols
$^{\circ}$
Achieved by: ^{\circ}
(This is the degrees sign!)

$\mathrm{C}$
Achieved by: \mathrm{C}
(This is to get non-italic text - for instance as in $^{\circ} \mathrm{C}$)

This post is still being added to! Please reply with any requests for things to be added to this basic list or clarifications. For anything not on this list, please refer to the site linked to at the top. Thank-you!

#2 Sublime Sunshine Posted Jun 09, 2011 - 15:17

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This is fantastic, thank you so much. This will make posting in math soo much easier.

Just a suggestion, to make it easier to use could you have a tex button like the code button or the subscript button? This would make it a lot easier than writing it out every time, or clicking on it in the styles list. This is generally because, when I use math here, I explain things while I'm doing it, which means that I have to rewrite the tag every time I use math.

#3 Ezeh Posted Jun 10, 2011 - 10:32

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Degree sign:
^{\circ}
Non-italic letter:
\mathrm{C}
$40^{\circ}\mathrm{C}$

\lim_{x \to +\infty}
$\lim_{x \to +\infty}$

\frac{du}{dt}
$\frac{du}{dt}$

v_{x}
$v_{x}$

Edited by Sandwich, Jun 11, 2011 - 15:46.
Thank-you! I've added them in :)

#4 chrypton Posted Jun 11, 2011 - 07:17

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Awesome guide Sandwich! I'll also give two helpful links:

Detexify - This site contains a white drawing area where you can draw a math symbol that you don't know the LaTeX code for. Very helpful.

AoPS LaTeX Guide - A comprehensive guide to using LaTeX. It also shows you how to create good-looking LaTeX documents.

Edited by Sandwich, Jun 11, 2011 - 15:46.
Awesome, thanks! I've added them both to the list :D

#5 Desy Glau Posted Jun 17, 2011 - 04:57

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7. Matrices
You then enter in the terms horizontally, so along the line, using & to indicate the next term e.g.
{1,1} & {1,2} & {1,3}

just to avoid confusion, I suggest the examples to just be
1 & 2 & 3
or
a & b & c
or anything along those lines, as simple as that instead of
{1,1} & {1,2} & {1,3}
because the {} brackets are rather confusing, as I thought we needed to put the brackets (or do we, actually?), although when I read the next example I saw that the brackets aren't necessary.

2. Indices
$x^7$
Achieved by: x^7

could you put in another example here e.g.:
$x^{-7}$
Achieved by: x^{-7}
because I initially thought it would just be x^-7 but then it became $x^-7$ and when I tried x^(-7) it became $x^(-7)$ and it turned out that we need to use {} instead

9. Operators

Trigonometry?

Edited by Desy Glau, Jun 17, 2011 - 04:59.

#6 Sandwich Posted Aug 31, 2011 - 10:40

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7. Matrices
You then enter in the terms horizontally, so along the line, using & to indicate the next term e.g.
{1,1} & {1,2} & {1,3}

just to avoid confusion, I suggest the examples to just be
1 & 2 & 3
or
a & b & c
or anything along those lines, as simple as that instead of
{1,1} & {1,2} & {1,3}
because the {} brackets are rather confusing, as I thought we needed to put the brackets (or do we, actually?), although when I read the next example I saw that the brackets aren't necessary.

Added your suggestions/changes. Re: the squiggly brackets, I've also added an explanation in as to why those are necessary for co-ordinates or negative numbers.

#7 Xydan Posted Sep 10, 2011 - 03:35

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Microsoft Word 2011 actually has a math writing function. Never bothered to figure out how it works exactly, but I believe it's just a simple "fill in the blanks."