vector calculus

A novel neutron source has been synthesized in the Department of Nuclear Engineering at Kyunghee University, and let's call it KHU-NFLUX. The neutron flux is given as follows depending on the location. The point source position is (0,0,0). F(x,y,z)=(5x3+12xy2,y3+eysinz,5z3+cycosz)1010/cm2sec When the distance from the source becomes 3cm, assuming that all neutrons are ahsorbed and there is no more flux. How many neutrons are emitted from the source per unit time