7.1 Integration By Parts/53

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

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

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