Dawson's integral is defined as follows:

$\mathrm{dawson}\left(2.5\right)$

$0.2230837222$

$\mathrm{diff}\left(\mathrm{dawson}\left(x\right)\,x\right)$

$1-2x\mathrm{dawson}\left(x\right)$

$\mathrm{convert}\left(\mathrm{dawson}\left(x\right)\,\mathrm{erf}\right)$

$\frac{-\frac{\mathrm{I}}{2}\sqrt{\mathrm{\pi }}\mathrm{erf}\left(\mathrm{I}x\right)}{{\ⅇ}^{x^2}}$