Solving an integral...

[OrangeOne]

? (-r^4 + (16-r^2)*(sqrt(16-r^2))*r) dr

I'm confused by the sqrt part among other things, can someone please help...

 

[pka]

Use the link below.
http://www.wolframalpha.com/input/?i=integrate+{-r^4+[16r^2*sqrt(16-r^2)]}dr