7.1 Integration By Parts/53

$y=xe^{-0.4x}~~~x=0,x=1$

Failed to parse (syntax error): {\displaystyle \underbrace{\int_{0}^{5}xe^{-0.4x}dx}_{ \begin{align} \begin{aligned} u &= x \quad dv= e^{-0.4x} dx \\[0.6ex] du &= dx \qquad v= \frac{5}{2}e^{-0.4x} \end{aligned} \\[2ex] \end{align} }

$\left[{\frac {5}{2}}e^{-0.4x}\right]+\int _{5}^{0}{\frac {5}{2}}e^{-0.4x}dx$