I'm just wondering where I've gone wrong. The correct answer to this question is ~6.38 but I end up with -47, which is not possible.

The question is to find the volume of the 'ice cream' shaped solid in the diagram below. My solution is also there. I think its the integral from 0 - pi/6 of Sin(phi) that's messing me up. I don't know why I end up with a negative number. .

Thanks Guys & Girls.