Where does this fraction come from in this integral?
So you have the integral:
I tried to do -substitution at first with , but I could not get the correct answer which is:
In the worked solution, they did not use a -substitution. The first integral becomes:
And I cannot see what technique they used to get that. I worked out that if you actually add the 2 fractions you end up back at the first integral, but I do not see how they worked out that is the way it should be re-arranged. I also don't understand why my -substitution didn't work. Should a -substitution have worked? I'm still trying to get my head around this integrating of fractions.