Answers

2016-06-28T04:05:34+08:00
Vol of sphere  =   4/3 π r³
  if r  =  x+1 
    vol   =  4/3 π (x+1)³      /   (x+1)³  =   x³ +3x² + 3x +1
    thus the vol  =        4/3 π(x³ +3x² + 3x + 1)
    to expand ( x + 1)³,  you need to know about the binomial theorem
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