Could someone check my answer for a volume of revolution question

I was hoping if someone could look over my solutions for the following questions, purely on the basis that I got an abnormally large answer and just want to double check if my solution is correct.

Question:http://i.gyazo.com/574a93dc75dc15b255c81e04028a1635.png
Solution: http://i.imgur.com/P6hvu5z.jpg

Thanks

if they want the exact value they do not want decimals... they want you to leave pi and e in the answer.

apart from that it is fine.

Is that (49Pi/2) e^3 or (49pi/2)(e^4 - 1) ?

the latter

Could you explain to me why its the latter one ? That what it says on the mark scheme but I really dont understand how its formed.
I see how it has factored out

Thanks for your help

Here you go: http://i.imgur.com/6MSI8G9.jpg