Posted by sharan on .
The mapping is f:N →N, given by F(n)= 2n^3+1,n belongs to N.
A. oneone and onto
B. onto not oneone
C. oneone not onto
D. neither oneone nor onto

maths 
Steve,
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.