Hello,

I was just in the middle of trying to solve this Integral when I got very confused.

This is the integral that I am trying to solve:

I will post the steps and then note when I get confused.

Step 2 (Integrate by Parts):

Step 3 (Integrate by Parts again):

Step 4 (Where I get lost):

I have no problem with integrating by parts, but I start to get lost when the integral left over on the right of the = sign is equal to the integral on the left of the = sign. How does the 5 come into play? What is that process that this problem goes through?

Your help is hugely appreciated!