posted by sharan .
The mapping is f:N →N, given by F(n)= 2n^3+1,n belongs to N.
A. one-one and onto
B. onto not one-one
C. one-one not onto
D. neither one-one nor onto
Think of the shape of the graph.
If we had f:R->R, it would be (A).
By restricting to N, it is (C), since many numbers (like 2) are not in the range.