Question

2)
a) Prove that 2^n > 4.n for n>=5.

b) Give an example, with justification, of a function with domain Z\{2,3} and co-domain
N. Is this function 1 – 1? Is it onto? Give reasons for your answers.

c) Give a set of cardinality 5 which is a subset of Z\N .

d) Check whether the relation R ={(x, y)belongs to N×N| xy is the square of an integer} is
an equivalence relation on N .