Let $f ( x ) = \left\lfloor x ^ { 3 } / 3 \right\rfloor$

Short Answer

Let $f ( x ) = \left\lfloor x ^ { 3 } / 3 \right\rfloor$ Finf (S) S is:
(a) {-2,-1,0,1,2,3} (b) {0,1,2,3,4,5} (c) }{1,5,7,11} . (d) }\{2,6,10,14}