Question

how to show a f(x) = x^2 +2 is not injective ​

Answer 1

Answer:

injective function means distinct elements in domain are mapped to distinct elements of co domain....

if we substitute some values like -2, -1, 0,1,2 we see that

f(-2) =f(2) =5

f(-1) =f(1) =3

f(0) =2

1 element in co domain should have 1 element of domain but here 1 element of co domain has 2 domains hence given func is not injective but its surjective