Math & Science ⇒ Problems with the cancel package

[Jonny Boy]

I having problems with the \cancelto command in the cancel package, in that if you close a bracket immediately after the command, the cancelled to value and the brackets merge into one.

The documentation makes reference to a makeroom package option, but can't seem to find how to use said option, so either instructions on the makeroom option, or another solution to the problem would be greatly appreciated.

Code: Select all

\documentclass[11pt]{amsart}
\usepackage{amssymb,a4wide,cancel}
\newcommand{\lb}{\left(}
\newcommand{\rb}{\right)}
\newcommand{\lsb}{\left[}
\newcommand{\rsb}{\right]}
\newcommand{\brac}[1]{\lb #1\rb}
\newcommand{\sqbrac}[1]{\lsb #1\rsb}
\newcommand{\intx}[3]{\int_{#2}^{#3} #1 \ dx}
\newcommand{\fpi}[2]{\frac{#1\pi}{#2}}

\begin{document}
\begin{align*}
\text{Volume}&=\pi\intx{\brac{\frac{3}{\sqrt{1+4x}}}^2}{0}{2} \\
&=\pi\intx{\frac{9}{1+4x}}{0}{2} \\
&=\fpi{9}{4}\intx{\frac{4}{1+4x}}{0}{2} \\
&=\fpi{9}{4}\sqbrac{\ln\brac{1+4x}}^2_0 \\
&=\fpi{9}{4}\sqbrac{\ln9-\cancelto{0}{\ln 1}}=\fpi{9}{4}\ln9
\end{align*}
\end{document}

[frabjous]

Seems to work just fine for me with the makeroom option, used as so:

Code: Select all

\documentclass[11pt]{amsart}
\usepackage{amssymb,a4wide}
\usepackage[makeroom]{cancel}
\newcommand{\lb}{\left(}
\newcommand{\rb}{\right)}
\newcommand{\lsb}{\left[}
\newcommand{\rsb}{\right]}
\newcommand{\brac}[1]{\lb #1\rb}
\newcommand{\sqbrac}[1]{\lsb #1\rsb}
\newcommand{\intx}[3]{\int_{#2}^{#3} #1 \ dx}
\newcommand{\fpi}[2]{\frac{#1\pi}{#2}}

\begin{document}
\begin{align*}
\text{Volume}&=\pi\intx{\brac{\frac{3}{\sqrt{1+4x}}}^2}{0}{2} \\
&=\pi\intx{\frac{9}{1+4x}}{0}{2} \\
&=\fpi{9}{4}\intx{\frac{4}{1+4x}}{0}{2} \\
&=\fpi{9}{4}\sqbrac{\ln\brac{1+4x}}^2_0 \\
&=\fpi{9}{4}\sqbrac{\ln9-\cancelto{0}{\ln 1}}=\fpi{9}{4}\ln9
\end{align*}
\end{document}

[Jonny Boy]

Thanks, that's great!