∫ e − x d x , u = − x ∫ e − x d x {\displaystyle {\begin{aligned}&\int {e^{-}x}dx\\[2ex],u=-x&\int {e^{-}x}dx\\[2ex]\end{aligned}}}
![{\displaystyle {\begin{aligned}&\int {e^{-}x}dx\\[2ex],u=-x&\int {e^{-}x}dx\\[2ex]\end{aligned}}}](https://en.wikipedia.org/api/rest_v1/media/math/render/svg/4e4a6b4c3bbf2492c109dc8596d61aec70b6e274)