How do you integrate x^2 e^-xx2ex?

1 Answer

It is

int x^2*e^-xdx=-e^-x*x^2+int e^-x2xdx=-x^2*e^-x-2x*e^-x+2*int e^-xdx=-e^-x*(x^2+2x+2)+cx2exdx=exx2+ex2xdx=x2ex2xex+2exdx=ex(x2+2x+2)+c

We used integration by parts

int f'(x)*g(x)dx=f(x)*g(x)-intf(x)*g'(x)dx