Q. $\int e^{x} \cdot x^{5} d x$ is

Solution:

$\int e^{x} x^{5} d x=x^{5} e^{x}-e^{x} \cdot 5 x^{4}+e^{x} \cdot 20 x^{3}-e^{x}, 60 x^{2}+e^{x} \cdot 120 x-e^{x} \cdot 120+c$.(by Bernoullis rule) $= e ^{x}\left[ x ^{5}-5 x ^{4}+20 x ^{3}-60 x ^{2}+120 x -120\right]+ c$