How do you integrate e^-lnx?

1 Answer
Apr 6, 2015

Use these two facts:

-lnx = ln x^(-1)=ln(1/x)

e^lnu = u

So,
int x^(-lnx) dx = int 1/x dx=ln absx+C.

Since the original function involves lnx, we are justified in assuming that x>0 and writing:

int x^(-lnx) dx =lnx+C.