# Thread: Integration problem

1. ## Integration problem

Hi,

I have a problem with this integration problem.If I have to integrate log_e(j^3) dj what method cna I use?..

Thanks,
NS

2. Originally Posted by NidhiS
Hi,

I have a problem with this integration problem.If I have to integrate log_e(j^3) dj what method cna I use?..

Thanks,
NS
note that you have $3 \int \ln j ~dj$

there are tons of ways to do this integral and they have been done on this site several times. you can do a search if you are so inclined. but i will tell you the conventional way to proceed. use integration by parts with $u = \ln j$ and $dv = dx$

recall the formula: $\int u~dv = uv - \int v~du$

3. I get it but What I dont understand is how did u pull out that 3?

4. Originally Posted by NidhiS
I get it but What I dont understand is how did u pull out that 3?
Because $\log x^3 = 3\log x$.
This is one of rules of logarithms.