Question

11. Let f be the subset of Z x Z defined by f = ((ab, a + b): a, b € Z). Is fa
function from Z to Z? Justify your answer.
2. Let A = 19,10,11,12,13) and let f:A-N be defined by f (n) = the highest prime
factor of n. Find the range of f.
PLEASE DO THAT BOTH ​

Answer 1

Answer:

Step-by-step explanation:

We observe that:

1 X 6 = 6 and 2 X 3 = 6

=>(1 X 6, 1 + 6) ∈ f and (2 X 3, 2 + 3) ∈ f

=>(6, 7) ∈ f and (6,5) ∈ f

So for element 6 we have two images which is not true in the case of any fucntion.  

Hence f is not a function.