# Package witharrows

I want to deal with the environment to insert explanations, like this: produced, on Overleaf, with the following commands:

\documentclass{article}
\usepackage[portuguese]{babel}
\usepackage[utf8]{inputenc}
\usepackage{fouriernc}
\usepackage{witharrows}
\usepackage{cancel}
\usepackage{amsmath}
\usepackage{tikz}

\renewcommand{\CancelColor}{\color{red}}

\begin{document}

$$\begin{WithArrows} \lim_{x \to +\infty} \left[ x \left( \sqrt{x^2-1} -x\right) \right] & = +\infty \left( \color{red}+\infty - \infty \right) \Arrow{Multiplicar e dividir pelo conjugado}\\ & = \lim_{x \to +\infty} \frac{\left( \sqrt{x^2-1} + x\right) \color{red} \left( \sqrt{x^2-1} -x\right)}{ \color{red} \left( \sqrt{x^2-1} -x\right) }\\ &= \lim_{x \to +\infty} \frac{x \left( \left( \sqrt{x^2-1} \right)^2 - x^2 \right)}{\sqrt{x^2-1} -x}\\ & = \lim_{x \to +\infty} \frac{x \left( \left( x^2-1 \right) - x^2 \right)}{\sqrt{x^2-1} -x} \\ & = \lim_{x \to +\infty} \frac{-x}{\sqrt{x^2-1} -x}\\ & = \lim_{x \to +\infty} \frac{-x}{\sqrt{x^2 \left( 1-\frac{1}{x^2} \right)} + x}\\ & = \lim_{x \to +\infty} \frac{-x}{\sqrt{x^2}\sqrt{1-\frac{1}{x^2}}+x}\\ & = \lim_{x \to +\infty} \frac{-x}{x \left( \sqrt{1-\frac{1}{x^2}}+1 \right)}\\ & = \lim_{x \to +\infty} \frac{-\cancel{x}}{\cancel{x}\left( \sqrt{1-\frac{1}{x^2}}+1\right)}\\ & = \lim_{x \to +\infty} \frac{-1}{\sqrt{1-\frac{1}{x^2}}+1} \\ & = \frac{-1}{\sqrt{1}+1}\\ & = -\frac{1}{2} \end{WithArrows}$$

\end{document}


Hoewver, when I use these command on Texmaker on my computer, an error message is given:

! Package witharrows Error: Your version of LaTeX (especially expl3) is too
(witharrows)                old. You can go on but you will probably have
(witharrows)                other errors if you use the functionalities of
(witharrows)                witharrows.

Type <return> to continue.
...

l.38 ...rror:nn { witharrows } { expl3~too~old } }

Try typing <return> to proceed.
If that doesn't work, type X <return> to quit.



How can I fix this, or find and install manually this package?

• Can you show the .log, please? Jan 29, 2021 at 0:19
• Above this is the log fraction. All content is too long. Jan 29, 2021 at 0:42
• Use pastebin.com or some other tool like that. The part of the .log you show is the error message that tells you to update expl3, so that's what you should do, but with the .log I might be able to give you more direct help Jan 29, 2021 at 0:48
• I think is a tex machine problem?? what are you using Miktex, Texlive???? version??? or How long has it been since you have done an update? this code runs fine in my machine with texlive2020 Jan 29, 2021 at 2:07
• Here my error: pastebin.com/up9LC7zQ I am with MiKTeX 2.9. I never made an update. Updating solves? Or need to re-install another version? Jan 29, 2021 at 13:15

(I'm the author of witharrows.)
This version of expl3 is too old to run the most recent versions of witharrows.