integral of (x^3e^x-8x^2)/(x^3)

解答

\int \frac{x ^{3} e ^{x} - 8 x ^{2}}{x ^{3}} d x

e^{x} - 8 ln ∣ x ∣ + C

求解步骤

\int \frac{x ^{3} e ^{x} - 8 x ^{2}}{x ^{3}} d x

乘开

\frac{x ^{3} e ^{x} - 8 x ^{2}}{x ^{3}} : e^{x} - \frac{8}{x}

= \int e^{x} - \frac{8}{x} d x

使用积分加法定则:

\int f (x) \pm g (x) d x = \int f (x) d x \pm \int g (x) d x

= \int e^{x} d x - \int \frac{8}{x} d x

\int e^{x} d x = e^{x}

\int \frac{8}{x} d x = 8 ln ∣ x ∣

= e^{x} - 8 ln ∣ x ∣

解答补常数

= e^{x} - 8 ln ∣ x ∣ + C

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