\[\mathscr{F}\left(f\right)\left(x\right)=\mathscr{F}\mskip-3.0muf\mskip 3.0mu%
\left(x\right)=\frac{1}{\sqrt{2\pi}}\int^{\infty}_{-\infty}f(t){\mathrm{e}}^{%
\mathrm{i}xt}\,\mathrm{d}t.\]