Check the injectivity and surjectivity of the following functions:

f : R R given by f (x) = x2


It is given that f : R R given by f (x) = x2

We can see that f(-1) = f(1) = 1, but -1 ≠ 1


f is not injective.


Now, let -2 ϵ R. But, we can see that there does not exists any x in R such that


f(x) = x2 = -2


f is not surjective.


Therefore, function f is neither injective nor surjective.


2
1