Aloha :)
Das funktioniert gut mit partieller Integration:$$I=\int\limits_0^{40}(108-2,7t)e^{0,1t}\,dt=108\int\limits_0^{40}e^{0,1t}\,dt-2,7\int\limits_0^{40}\underbrace{t}_{=u}\cdot\underbrace{e^{0,1t}}_{=v'}\,dt$$$$\phantom I=108\left[\frac{e^{0,1t}}{0,1}\right]_0^{40}-2,7\left(\left[\underbrace{t}_{=u}\cdot\underbrace{\frac{e^{0,1t}}{0,1}}_{=v}\right]_0^{40}-\int\limits_0^{40}\underbrace{1}_{=u'}\cdot\underbrace{\frac{e^{0,1t}}{0,1}}_{=v}\,dt\right)$$$$\phantom I=\left(1080e^{4}-1080\right)-2,7\cdot\left(400e^4-0\right)+27\int\limits_0^{40}e^{0,1t}\,dt$$$$\phantom I=-1080+27\left[\frac{e^{0,1t}}{0,1}\right]_0^{40}=-1080+270e^4-270=270e^4-1350\approx13\,391,5005\ldots$$