The Attempt at a Solution
Firstly, I set
Then take the derivative,
Now I integrated. So
(1/3) * [(x^2+a^2)^3/2] from a to 0.
I ended up with
This is where I get lost. It must have something to do with the (A>0). The answer in the book is:
I can't see how to eliminate the a's to get the (2*sqrt(2)-1).
Thanks for the help.