I totally blanked on this. I need to find the derivative of the volume of a hemispherical balloon. From the picture i can tell that the volume, = . For some reason I totally blanked on how to get the derivative of a sphere and cylnder. This is what i got, but I am not sure it is correct. Could someone double check please? Thanks

=

I think i messed up somewhere but not sure where, just as a clarification, is the rate of change of the radius in relation to time.

Thanks for helping!