I am writing equations in wikidocs using markdown and latex.
I tried to align the equations along the equal sign but I can't find the solution. The following is the latex that I wrote currently.
$$\begin{align}
Then,\ (x+z)+t & = x+(z+t)\ (\because Rule2) \\
& = x+0_V \\
& = x\ (\because Rule3) \\
\end{align}$$
The following is the resulted equation on the wikidocs.
I found this link
R Markdown Math Equation Alignment, but I still don't know what the problem is. Could you help me please?
As $$...$$ establishes an equation math mode environment, as does \begin{align}, it is not possible to use the align environment inside $$...$$; it can only be used (in real LaTeX source, that is) outside math mode, because it wants to switch to math mode all by itself.
You should use \begin{aligned}...\end{aligned} — note ist's aligned, not align —, as that is an environment meant to be used inside math mode. As such it is suited for use inside the $$...$$ fencing.
I ran your code on my system and it aligns just fine. Make sure you have the latest version of tools and packages installed. A minimal working example would be useful too.
The equation below does not display in latex. Also, the introductory text does not display properly(all words together without space and in italics)
A common form of this potential is the 12-6 Lennard Jones (LJ) potential
expressed as equation 2.7
\begin{align}
U_{ij}= 4\epsilon_{ij}[(\frac{\sigma_{ij}}{r_{ij})^12-
(\frac{\sigma_{ij}}{r_{ij})^6]
\end{align}
Also, in the text below, all words are together without space and in italics.
Where \epsilon_{ij} and \sigma{ij} represent well depth and diameter of
the atom respectively. \epsilon_{ij} and \sigma_{ij} for unlike atoms
are determined using Lorentz-Berthelot combination rules [44] given in
equations 2.8 and 2.9
Your help is appreciated.
I attach here a picture of the output.
This is because you're not using inline math mode properly. In the image you posted
it shows that your text is preceded by (what looks like) \epsilon_{ij}. \epsilon requires a math font, and therefore you should use $\epsilon_{ij}$. The same goes for any inline math you want to typeset. This would be the suggested/proper coding:
A common form of this potential is the 12-6 Lennard Jones (LJ) potential
expressed as equation~\eqref{eq:lj-potential},
\begin{equation}
U_{ij} = 4 \epsilon_{ij} [ (\frac{\sigma_{ij}}{r_{ij})^{12}
- (\frac{\sigma_{ij}}{r_{ij})^6 ] \label{eq:lj-potential}
\end{equation}
where $\epsilon_{ij}$ and $\sigma{ij}$ represent well depth and diameter of
the atom respectively. $\epsilon_{ij}$ and $\sigma_{ij}$ for unlike atoms
are determined using Lorentz-Berthelot combination rules~\cite{lorentz-berthelot}
given in equations~\eqref{eq:epsilon} and~\eqref{eq:sigma}.
Note the following:
Use equation for a single-line numbered equation; align is for multi-line equations (that may require alignment).
No blank line (paragraph break) before equation.
Use \labels and \refs (or \eqref, since you're using amsmath) since equation numbers can change. Let TeX take care of storing and recalling these numbers.
Use \cite to reference something in a bibliography.
Use $...$ (or \(...\)) for inline math (already discussed above).
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
U_{ij}= 4\epsilon_{ij}[
(\frac{
\sigma_{ij}
}{
(r_{ij})^{12} -
\frac{
\sigma_{ij}
}{(r_{ij})^6
}
}]
\end{align}
\end{document}
three groups were not closed properly in the equation.
Read about amsmath package.
I suggest you try to write as clean as possible.
Output
It seems to be common practice, when writing mathematics, to add punctuation to displayed formulas.
Is there any trick to avoid putting the punctuation mark inside the formula?
I want to avoid
Consider the function
\[ \sin(x).\]
I'd rather have something like:
Consider the function
\[ \sin(x)\].
But of course the full stop is displayed below the formula.
Is there a clever way to separate formulas and punctuation in LaTeX?
\catcode`\#=11
\let\seveendformula\]
\def\]{\#ifnextchar.\PointAndEndFormula\seveendformula}
\def \PointAndEndFormula #1{.\seveendformula}
\catcode`\#=12
Add
More complex solution works with .,?!;: :
\catcode`\#=11
\def\addtopunct#1{\expandafter\let\csname punct#\meaning#1\endcsname\let}
\addtopunct{.} \addtopunct{,} \addtopunct{?}
\addtopunct{!} \addtopunct{;} \addtopunct{:}
\let\seveendformula\]
\def\PunctAndEndFormula #1{#1\seveendformula}
\def\]{\futurelet\punctlet\checkpunct#i}
\def\checkpunct#i{\expandafter\ifx\csname punct#\meaning\punctlet\endcsname\let
\expandafter\PunctAndEndFormula
\else \expandafter\seveendformula\fi}
\catcode`\#=12
There's also the issue of which font the punctuation should be in. You won't see a problem until you try a different math font such as Euler. Then commas and periods are clearly different in text mode and in math mode. I've written text-mode punctuation in displayed formulas as \mbox{,} or lazily as \mbox, just before $$.
You can load the breqn package (compatible with amsmath) and have this behaviour inbuilt with its dmath environment:
Consider the function
\begin{dmath}\sin(x)\end{dmath}.
Will output the same as \[\sin(x).\], i.e., as if the dot was inside the expression.
As a bonus, you'll also get automatic line-breaking in your math equation.
Putting the punctuation inside a display environment is the usual way. The problem is that when Latex processes the \], it ends the mathbox, so anything following will be part of a new vertical box.
You could try something like:
\hbox{\[My formula\]}.
This is not tested, and probably has spacing issues, but if you are interested in this kind of solution, I could try and get something working.
FWIW, you might be interested in https://mathoverflow.net/questions/6675/periods-and-commas-in-mathematical-writing
When I write math in LaTeX I often need to perform simple arithmetic on numbers in my LaTeX source, like 515.1544 + 454 = ???.
I usually copy-paste the LaTeX code into Google to get the result, but I still have to manually change the syntax, e.g.
\frac{154,7}{25} - (289 - \frac{1337}{42})
must be changed to
154,7/25 - (289 - 1337/42)
It seems trivial to write a program to do this for the most commonly used operations.
Is there a calculator which understand this syntax?
EDIT:
I know that doing this perfectly is impossible (because of the halting problem). Doing it for the simple cases I need is trivial. \frac, \cdot, \sqrt and a few other tags would do the trick. The program could just return an error for cases it does not understand.
WolframAlpha can take input in TeX form.
http://blog.wolframalpha.com/2010/09/30/talk-to-wolframalpha-in-tex/
The LaTeXCalc project is designed to do just that. It will read a TeX file and do the computations. For more information check out the home page at http://latexcalc.sourceforge.net/
The calc package allows you to do some calculations in source, but only within commands like \setcounter and \addtolength. As far as I can tell, this is not what you want.
If you already use sage, then the sagetex package is pretty awesome (if not, it's overkill). It allows you get nicely formatted output from input like this:
The square of
$\begin{pmatrix}
1 & 2 \\
3 & 4
\end{pmatrix}$
is \sage{matrix([[1, 2], [3,4]])^2}.
The prime factorization of the current page number is \sage{factor(\thepage)}
As Andy says, the answer is yes there is a calculator that can understand most latex formulas: Emacs.
Try the following steps (assuming vanilla emacs):
Open emacs
Open your .tex file (or activate latex-mode)
position the point somewhere between the two $$ or e.g. inside the begin/end environment of the formula (or even matrix).
use calc embedded mode for maximum awesomeness
So with point in the formula you gave above:
$\frac{154,7}{25} - (289 - \frac{1337}{42})$
press C-x * d to duplicate the formula in the line below and enter calc-embedded mode which should already have activated a latex variant of calc for you. Your buffer now looks like this:
$\frac{154,7}{25} - (289 - \frac{1337}{42})$
$\frac{-37651}{150}$`
Note that the fraction as already been transformed as far as possible. Doing the same again (C-x * d) and pressing c f to convert the fractional into a floating point number yields the following buffer:
$\frac{154,7}{25} - (289 - \frac{1337}{42})$
$\frac{-37651}{150}$
$-251.006666667$
I used C-x * d to duplicate the formula and then enter embedded mode in order to have the intermediate values, however there is also C-x * e which avoids the duplication and simply enters embedded mode for the current formula.
If you are interested you should really have a look at the info page for Emacs Calc - Embedded Mode. And in general the help for the Gnu Emaca Calculator together with the awesome interactive tutorial.
You can run an R function called Sweave on a (mostly TeX with some R) file that can replace R expressions with their results in Tex.
A tutorial can be found here: http://www.scribd.com/doc/6451985/Learning-to-Sweave-in-APA-Style
My calculator can do that. To get the formatted output, double-click the result formula and press ctrl+c to copy it.
It can do fairly advanced stuff too (differentiation, easy integrals (and not that easy ones)...).
https://calculator-algebra.org/
A sample computation:
https://calculator-algebra.org:8166/#%7B%22currentPage%22%3A%22calculator%22%2C%22calculatorInput%22%3A%22%5C%5Cfrac%7B1%2B2%7D%7B3%7D%3B%20d%2Fdx(arctan%20(2x%2B3))%22%2C%22monitoring%22%3A%22true%22%7D
There is a way to do what you want just not quite how you describe.
You can use the fp package (\usepackage[options]{fp}) the floating point package will do anything you want; solving equations, adding dividing and many more. Unfortunately it will not read the LaTeX math you instead have to do something a little different, the documentation is very poor so I'll give an example here.
for instance if you want to do (2x3)/5 you would type:
\FPmul\p{2}{3} % \p is the assignment of the operation 2x3
\FPupn\p{\p{} 7 round} % upn evaluates the assignment \p and rounds to 7dp
\FPdiv\q{\p}{5} % divides the assigned value p by 5 names result q
\FPupn\q{\q{} 4 round} % rounds the result to 4 decimal places and evaluates
$\frac{2\times3}{5}=\FPprint\q$ % This will print the result of the calculations in the math.
the FP commands are always ibvisible, only FPprint prints the result associated with it so your documents will not be messy, FP commands can be placed wherever you wish (not verb) as long as they are before the associated FPprint.
You could just paste it into symbolab which as a bonus has free step by step solutions. Also since symbolab uses mathquill it instantly formats your latex.
Considering that LaTeX itself is a Turing-complete markup language I strongly doubt you can build something like this that isn't built directly into LaTeX. Furthermore, LaTeX math matkup itself has next to no semantic meaning, it merely describes the visual appearance.
That being said, you can probably hack together something which recognizes a non-programmable subset of LaTeX math markup and spits out the result in the same way. If all you're interested in is simple arithmetics with fractions and integers (careful with decimal fractions, though, as they may appear as 3{,}141... in German texts :)) this shouldn't be too hard. But once you start with integrals, matrices, etc. I fear that LaTeX lacks expressiveness to accurately describe your intentions. It is a document preparation system, after all and thus not very suitable as input for computer algebra systems.
Side note: You can switch to Word which has—in its current version—a math markup language which is sufficiently LaTeX-like (by now it even supports LaTeX markup) and yet still Google-friendly for simpler terms:
With the free Microsoft Math add-in you can even let Word calculate expressions in-place:
There is none, because it is generally not possible.
LaTeX math mode markup is presentational markup and there are cases in which it does not provide enough information to calculate the expression.
That was one of the reasons MathML content markup was created and also why MathML is used in Mathematica. MathML actually is sort of two languages in one:
presentation markup
content markup
To accomplish what you are after you'll have to have MathML with comibned presentation and content markup (see MathML spec).
In my opinion your best bet is to use MathML (even if it is verbose) and convert to LaTeX when necessary. That said, I also like LaTeX syntax best and maybe what we need is a compact syntax for MathML (something similar in spirit to RelaxNG compact syntax).
For calculations with LaTeX you can use a CalcTeX package.
This package understand elements of LaTeX language and makes an calculations, for example your problem is avialble on
http://sg.bzip.pl/CalcTeX/examples/frac.tgz
or just please write
\noindent
For calculation please use following enviromentals
$515.1544 + 454$
or
\[ \frac{154.7}{25}-(289-\frac{1337}{42.})
\]
or
\begin{equation}
154.7/25-(289-1337/42.)
\end{equation}
For more info please visite project web site or contact author of this project.
For performing the math within your LaTeX itself, you might also look into the pgfmath package, which is more powerful and convenient than the calc package. You can find out how to use it from Part VI of The TikZ and PGF Packages Manual, which you can find here (version 2.10 currently): http://mirror.unl.edu/ctan/graphics/pgf/base/doc/generic/pgf/pgfmanual.pdf
Emacs calc-mode accepts latex-input. I use it daily. Press "d", followed by "L" to enter latex input mode. Press "'" to open a prompt where you can paste your tex.
Anyone saing it is not possible is wrong.
IIRC Mathematica can do it.
There is none, because it is generally not possible. LaTeX math mode
markup is presentational markup and there are cases in which it does
not provide enough information to calculate the expression.
You are right. LaTeX as it is does not provide enough info to make any calculations.Moreover, it does not represent any information to do it. But nobody prevents to wright in LaTeX format a text that contains such an information.
It is a difficult path, because you need to build a system of rules superimposed on what content ofthe text in Latex format needs to contain that it would be recognizable by your interpreter. And then convince the user that it is necessary to learn, etc. etc...
The easiest way to create a logical and intuitive calculator of mathematical expressions. And the expression is already possible to convert latex. It's almost like what you said. This is implemented in the program which I have pointed to. AnEasyCalc allows to type an expression as you type the plane text in any text editor. It checks, calculates and generate LateX string by its own then. Its very easy and rapid work. Just try and you will see that.
This is not exactly what you are asking for but it is a nice package
that you can include in a LaTeX document to do all kind of operations including arithmetic, calculus and even vectors and matrices:
The package name is "calculator"
http://mirror.unl.edu/ctan/macros/latex/contrib/calculator/calculator.pdf
The latex2sympy2 Python library can parse LaTeX math expressions.
from latex2sympy2 import latex2sympy
tex_str = r"""YOUR TEX MATH HERE"""
tex_str = r"\frac{9\pi}{\ln(12)}+22" # example TeX math
sympy_object = latex2sympy(tex_str)
evaluated_tex = float(sympy_object.evalf())
print(evaluated_tex)
This Python 3 code evaluates 9𝜋/ln(12)+22 (in its LaTeX from above) to 33.37842899841745.
The snippet above only handles basic algebraic simplification (math expressions without variables). Since the library converts LaTeX math to SymPy objects, the above code can easily be tweaked and extended to handle much more complicated LaTeX math (including solving derivatives, integrals, etc...).
The latex2sympy2 library can be installed via the pip command: pip install --user latex2sympy2
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try the AnEasyCalc program. It allows to get the latex formula very easy:
http://steamandwater.od.ua/AnEasyCalc/
:)