331. LaTeX技巧328：cancel宏包的使用方法

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常见数学公式问题集下载

cancel宏包主要用在数学环境中，推理或者运算式子中。用以说明。
示例如下图：


示例代码：
\usepackage{amsmath}
\usepackage{cancel}

\begin{align*}
& \sum_{k=1}^n [1/k - 1/(k+1)] \\
&= [1-1/2]+[1/2-1/3]+\cdots+[1/n-1/(n+1)] \\
&= [1-\cancel{1/2}]+[\cancel{1/2}-\cancel{1/3}]+[\cancel{1/3}-\cancel{1/4}]\cdots+[\cancel{1/n}-1/(n+1)] \qquad \text{(\texttt{\cancel})}\\
&= [1-\bcancel{1/2}]+[\bcancel{1/2}-\bcancel{1/3}]+[\bcancel{1/3}-\bcancel{1/4}]\cdots+[\bcancel{1/n}-1/(n+1)] \qquad \text{(\texttt{\bcancel})}\\
&= [1-\xcancel{1/2}]+[\xcancel{1/2}-\xcancel{1/3}]+[\xcancel{1/3}-\xcancel{1/4}]\cdots+[\xcancel{1/n}-1/(n+1)] \qquad \text{(\texttt{\xcancel})}\\
&=1-1/(n+1)
\end{align*}

2
$$
\bcancel{a+b}
$$

3
$$
a+\xcancel{b-b}
$$

4
$$
\cancelto{1234}{123+1234-123}
$$

$$
\cancelto{\text{Is it right?}}{\frac 12 +\frac 13 = \frac 25}
$$