A hemispherical water tank 20 feet across the top is filled with water. Find the work required to pump all the water to 6 feet above the top of the tank. Draw a sketch and label the coordinate system that you use.

my question is how is the integration equation supposed to look like? can someone give me the equation? my prof makes mistakes so much. I think he left out the 6 feet part in the equation; you dont see a 6 anywhere in it.