\int x^{2} e^{x} d x= ?
(A) \frac{e^{x^{3}}}{3}+k
(B) \frac{1}{3} e^{x^{2}}+k
(C) \frac{e^{x^{3}}}{2}+k
(D) \frac{1}{2} e^{x^{2}}+k
\int x^{2} e^{x} d x= ?
(A) \frac{e^{x^{3}}}{3}+k
(B) \frac{1}{3} e^{x^{2}}+k
(C) \frac{e^{x^{3}}}{2}+k
(D) \frac{1}{2} e^{x^{2}}+k

Integrating by parts,

    \[\begin{array}{l} \mathrm{u}=\mathrm{x}^{2}, \mathrm{v}=\mathrm{e}^{\mathrm{x}} \\ \mathrm{u}^{\prime}=2 \mathrm{x}, \int \mathrm{vdx}=\mathrm{e}^{\mathrm{x}} \\ \Longrightarrow \mathrm{x}^{2} \mathrm{e}^{x}-\int 2 \mathrm{xe}^{\mathrm{x}} \mathrm{dx} \end{array}\]

Again integrating by parts, we get

    \[\begin{array}{l} \mathrm{u}=\mathrm{x}, \mathrm{v}=\mathrm{e}^{x} \\ \mathrm{u}^{\prime}=1, \int \mathrm{vdx}=\mathrm{e}^{x} \\ \Longrightarrow \mathrm{x}^{2} \mathrm{e}^{x}-2 \mathrm{xe}^{\mathrm{x}}+2 \int \mathrm{e}^{\mathrm{x}} \mathrm{dx} \\ \Longrightarrow \mathrm{x}^{2} \mathrm{e}^{x}-2 \mathrm{xe}^{\mathrm{x}}+2 \mathrm{e}^{\mathrm{x}}+\mathrm{c} \end{array}\]