@ Stig:

Thanks for the working LegioXXXUlpiaVictrix, I know exactly what I did wrong now. When integrating I divided the constant and the index wrongly. ()

Quote Originally Posted by The_Mark
We might as well compare educational systems while at it
I take it you do this stuff at Uni then? I've got to do it at school, quite irritating really. And questions like these are pretty common in our assessments. The hardest one I've ever got was:

A hemispherical bowl of radius a units is filled with water to a depth of a/2 units. Find, by integration, the volume of the water.

The teacher couldn't even do it, I'm proud to say that it took me under 5 minutes to do it.