Real operations in LaTex - latex

This is a piece of my code.
\newcommand{\number}{2}
\number + 2
Is there any way that a '4' is written instead a '2+2'? (LaTex does the real operation).
Thanks

There are many possibilities to do calculations in latex. Just one option is pgfmath:
\documentclass{article}
\usepackage{tikz}
\begin{document}
\newcommand{\mynumber}{2}
\pgfmathparse{\mynumber+2}
\pgfmathresult
\end{document}

Related

Using numbers as input in \newenvironment LaTeX

I'm trying to make an environment that builds a column vector, and that takes as input the scale factor of the distancing between the rows:
\newenvironment{VEC}[1]{\begin{Bmatrix}\renewcommand{\arraystretch}{#1}}
{\end{Bmatrix}}
I know that the \newenvironment command accepts as input only strings, so I tried with \value{#1} having no successfull result. Any help would be appreciated.
Nothing to do with newenvironment or arguments, you just need to switch the order:
\documentclass{article}
\usepackage{mathtools}
\newenvironment{VEC}[1]{\renewcommand{\arraystretch}{#1}\begin{Bmatrix}}
{\end{Bmatrix}}
\begin{document}
\[
\begin{VEC}{3}
4\\
6\\
\end{VEC}
\]
\end{document}

LaTex how to edit this equation?

I'm having issues turning this word equation into a LaTex equation. It's coming out looking dodgy, please help!
I added a screen shot of the equation I want, and what I end up getting when I copy and paste into LaTex:
WORD:
LATEX CODE:
\mathrm{=\ }\mathrm{C}_\mathrm{0}\mathrm{[1-}6(Dt)1/2aπ2-3Dta2] + 12(Dt)1/2an = 1∞exp(na(Dt)1/2)
and therefore nothing comes out and LaTex doesn't let me run it.
This is absolutely not a proper LaTeX equation code. I don't know what you know about LaTeX, but you cannot just copy and paste from Word or any software to you LaTex editor. Plus, you need to provide your full code for anyone being able to help you.
Anyway, running this MWE should work :
\documentclass[11pt, a4paper, twoside]{report}
% ===== PACKAGES DECLARATION =====
\usepackage{mathtools} % Replaces amsmaths + more features
\usepackage{amsfonts} % Maths fonts package
% ===== DOCUMENT BODY =====
\begin{document}
\begin{equation} % optional : use the "equation*" environment to remove equation number
% optional : use traditional math font by removing the \mathrm{} command
\mathrm{X = C_0 \left[ 1 - \frac{6(Dt)^{1/2}}{a \pi^2} - \frac{3Dt}{a^2}\right] + \frac{12(Dt)^{1/2}}{a} \sum_{n=1}^\infty \exp\left(\frac{na}{(Dt)^{1/2}} \right)}
% optional : remove auto-sized brackets by removing the \left and \right commands
\end{equation}
\end{document}
As written in the code, you may want to remove the equation number and the big auto-sized brackets (that are more readable in my opinion). Just remove the corresponding commands. Also, you should consider using the "normal" math font and not the roman one that is clearly different from the text and helps the reader to separate equations from inline small expressions you could insert in your document.
One first sketch:
\documentclass{article}
\begin{document}
\[
C_0\left[1-\frac{6(Dt)^{\frac{1}{2}}}{a\pi^2}-\frac{3Dt}{a^2}\right]+%
\frac{12(Dt)^{\frac{1}{2}}}{a}\sum^{\infty}_{n=1}%
\exp\left(\frac{na}{(Dt)^{\frac{1}{2}}}\right)
\]
\end{document}
No packages required. The output:
Than you can tune the math fonts and anything else.

Does anyone know the code for the symbol less than or greater than \lessgtr in latex

Need to know the code for symbol less than or greater than in this format:
Note: detexify and the comprehensive book of symbols were with no help.
Also this one is depreciated:
\lessgrt\limits_{noise}^{speech}
Like this?
\documentclass{article}
\usepackage{amssymb}
\begin{document}
\[
y_k \mathop{\lessgtr}_{noise}^{speech} \eta
\]
\end{document}

How to use Phonetic Symbols in LaTex

How to use inverted A character(Phonetic Symbol) in an equation in LaTex? Do I have to use any specific package for it? I used \textinvsca, but it says "undefined control sequence"
There are a myriad of ways you can achieve this. Most notably, consult How to look up a symbol or identify a math symbol or character?.
This reveals you need tipa (more specifically, \usepackage{tipx}):
\documentclass{article}
\usepackage{tipx}
\begin{document}
A\textsc{a}\textinvsca\textsc{a}A
\end{document}
You can also rotate-and-scale a regular A:
\documentclass{article}
\usepackage{graphicx}
\newcommand{\textinvsca}{%
\reflectbox{%
\rotatebox[origin=c]{180}{%
\resizebox{!}{.35\baselineskip}{\textsc{A}}}}}
\begin{document}
A\textsc{a}\textinvsca\textsc{a}A
\end{document}
\forall is the universal quantifier:

How to get the value of the document title in latex?

I am wondering how I can get the document title in LaTex, for use elsewhere in the document. I just want to be able to echo it.
Using \#title does not work because \maketitle clears \#title. This seems silly to me but that's the way it is. One solution is to redefine \title to save the title somewhere else. For instance,
\def\title#1{\gdef\#title{#1}\gdef\THETITLE{#1}}
then use \THETITLE.
You can do the other way around: \def\MYTITLE{...} then \title{\MYTITLE} and later use \MYTITLE again.
I had success just writing a new command.
\newcommand{\mytitle}{...}
\title{\mytitle}
There is a package called authoraftertitle that does exactly this
\documentclass{article}
\usepackage{authoraftertitle}
\setlength\parindent{0 pt}
\begin{document}
\title{a good title}
\author{a better author}
\date{the best date}
\maketitle
the title is: \textbf{\MyTitle} \\
the author is: \textbf{\MyAuthor} \\
the data is: \textbf{\MyDate} \\
\end{document}
This is a workaround...
\let\titleoriginal\title % save original \title macro
\renewcommand{\title}[1]{ % substitute for a new \title
\titleoriginal{#1}% % define the real title
\newcommand{\thetitle}{#1} % define \thetitle
}
\title{This is my title}
\begin{document}
\thetitle
\end{document}
The short version of the title was ignored here...

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