# Can't solve this integral

1. Sep 20, 2010

### KillaKem

1. The problem statement, all variables and given/known data

Find the integral, I , of the followin' function.

2. Relevant equations

$$\int \frac{dx}{4 - lnx}$$.

3.Attempt

U = sqrt(lnx)
dx = 2xlnx du

Therefore

$$\int \frac{2xlnxdu}{4 - U^2}$$.

Integration of this f(x) failed

These are all integrals we have dealt with

http://www.mathwords.com/i/integral_table.htm

Last edited: Sep 20, 2010
2. Sep 20, 2010

### gabbagabbahey

There is no closed-form solution in terms of elementary functions, but if you use the substitution $u=4-\ln(x)$, you can express the integral in terms of the special function called exponential integral function.