5.1 Writing formulas in TeX
From Förberedande kurs i matematik 1
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'''Contents:''' | '''Contents:''' | ||
+ | * What is TeX/LaTeX? | ||
+ | * Common expressions | ||
+ | * Common mistakes | ||
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After this section you will have learned how to: | After this section you will have learned how to: | ||
- | * | + | * Write formulas in TeX |
- | + | ||
}} | }} | ||
+ | |||
+ | ==What is TeX/LaTeX?== | ||
+ | |||
+ | ==Common expressions == | ||
==Common mistakes== | ==Common mistakes== |
Revision as of 12:52, 27 January 2009
Theory | Exercises |
Contents:
- What is TeX/LaTeX?
- Common expressions
- Common mistakes
Learning outcomes:
After this section you will have learned how to:
- Write formulas in TeX
What is TeX/LaTeX?
Common expressions
Common mistakes
One of the most common mistakes when editing math in the wiki is to forget the start <math> tag and the end </math> tag.
Remember also to start commands with a backslash (\) and to add a space after the commands (unless they are followed immediately by a new command).
Another frequent mistake is to use an asterisk (*) instead of a proper multiplication sign
Example
TeX | Result | |
| sin x | |
| \sinx | Error |
| \sin x | |
| 4*3 | ![]() |
| 4\times 3 | ![]() |
| a\times b | ![]() |
| ab |
Exponents and indices
When writing exponents you use ^ followed by the exponent and to write indices you use _ followed by the index. If the exponent or index consists of more than one symbol it must be enclosed with braces {}.
A special kind of exponent is the degree sign (°) which is written as ^{\circ}.
Example
TeX | Result | |
| a2 | |
| a^2 | |
| x1 | |
| x_1 | |
| a^22 | |
| a^{22} | |
| 30^{o} | |
| 30^{0} | |
| 30^{\circ} | ![]() |
Delimiters
In more complex expressions you need to make sure to balance each opening parenthesis ( with a closing parenthesis ).
A pair of parenthesis that delimits a tall expression should be as large as the expression. You should therefore prefix the opening parenthesis with \left and the closing parenthesis with \right to get a pair of extensible parentheses that adjust its height to the expression.
Note also that braces {} and not parentheses () are used in commands to delimits arguments.
Example
TeX | Result | |
| (1-(1-x) | |
| (1-(1-x)) | |
| (\dfrac{a}{b}+c) | |
| \left(\dfrac{a}{b}+c\right) | ![]() ![]() |
| \frac(1)(2) | |
| \frac{1}{2} | |
| \sqrt(a+b) | ![]() |
| \sqrt{(a+b)} | ![]() |
| \sqrt{a+b} | ![]() |
Fractions
As a rule of thumb you should write fractions where the numerator and denominator consist only of a few digits as a small fraction (i.e. with \tfrac), while other fractions should be large (i.e. with \frac).
If an exponent or index contains a fraction then that fraction should be written in a slashed form (e.g. 2
Example
TeX | Result | |
| \dfrac{1}{2} | |
| \frac{1}{2} | |
| ||
| \frac{a}{b} | |
| \dfrac{a}{b} | |
| \frac{\sqrt{3}}{2} | ![]() |
| \dfrac{\sqrt{3}}{2} | \displaystyle \dfrac{\sqrt{3}}{2} |
| a^{\frac{1}{2}} | \displaystyle a^{\frac{1}{2}} |
| a^{1/2} | \displaystyle a^{1/2} |
Study advice
Useful web sites
- A video course in mathematical writing by Donald Knuth (A compendium accompaning the course is avalable in source form or in excerpts from Google books).