Integraal van $$$\frac{t^{2} e^{- x^{2}}}{u}$$$ met betrekking tot $$$x$$$

Bepaal $$$\int \frac{t^{2} e^{- x^{2}}}{u}\, dx$$$.

Pas de constante-veelvoudregel $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ toe met $$$c=\frac{t^{2}}{u}$$$ en $$$f{\left(x \right)} = e^{- x^{2}}$$$:

$${\color{red}{\int{\frac{t^{2} e^{- x^{2}}}{u} d x}}} = {\color{red}{\frac{t^{2} \int{e^{- x^{2}} d x}}{u}}}$$

Deze integraal (Foutfunctie) heeft geen gesloten vorm:

$$\frac{t^{2} {\color{red}{\int{e^{- x^{2}} d x}}}}{u} = \frac{t^{2} {\color{red}{\left(\frac{\sqrt{\pi} \operatorname{erf}{\left(x \right)}}{2}\right)}}}{u}$$

Dus,

$$\int{\frac{t^{2} e^{- x^{2}}}{u} d x} = \frac{\sqrt{\pi} t^{2} \operatorname{erf}{\left(x \right)}}{2 u}$$

Voeg de integratieconstante toe:

$$\int{\frac{t^{2} e^{- x^{2}}}{u} d x} = \frac{\sqrt{\pi} t^{2} \operatorname{erf}{\left(x \right)}}{2 u}+C$$

$$$\int \frac{t^{2} e^{- x^{2}}}{u}\, dx = \frac{\sqrt{\pi} t^{2} \operatorname{erf}{\left(x \right)}}{2 u} + C$$$A