\[\frac{\mathrm{d}}{\mathrm{d}x}\left({\mathrm{e}}^{-x}x^{\alpha}L^{(\alpha)}_{n%
}\left(x\right)\right)=(n+1){\mathrm{e}}^{-x}x^{\alpha-1}L^{(\alpha-1)}_{n+1}%
\left(x\right).\]