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\usepackage{xepersian}
\begin{document}
\begin{tabular}{@{}|c|c|c|cl@{}}\hline
\multicolumn{4}{@{}|c|@{}}{\rule{0mm}{0.9cm}%
\mbox{تبدیل لاپلاس برخی از توابع}}\\
\hline
F(s)&f(t)&F(s)&f(t)|\\
\hline
\rule {0mm}{0.9cm}
$k\frac{s}{s^{2}+a^{2}}\quad,\quad(s>0)$&$k\cos at$& $\frac{a}{s}\quad,\quad(s>a)$&$a$\\
\hline
\rule {0mm}{0.9cm}
$k\frac{a}{s^{2}+a^{2}}\quad,\quad (s>a)$&$k\sin at$&$a\frac{n!}{s^{n+1}}\quad,\quad (s>0)$&$at^{n}$\\
\hline
\rule {0mm}{0.9cm}
$k\frac{s}{s^{2}-a^{2}}\quad,\quad (s>|a|)$&$k\cosh at$&$k\frac{\Gamma(a+1)}{s^{a+1}}\quad,\quad(s>0)$&$kt^{a}, a>-1$\\
\hline
\rule {0mm}{0.9cm}
$k\frac{a}{s^{2}-a^{2}}\quad,\quad(s>|a|)$&$k\sinh at$&$\frac{k}{s-a}\quad,\quad (s>A)$&$ke^{at}$\\
\hline
\end{tabular}
\end{document}