f: R → R be defined as f(x) = x4.
Let x, y ϵ R such that f(x) = f(y)
⇒ x4 = y4
⇒ x = y
Therefore, f(x1) = f(x2) which does not implies x1 = x2.
For instance, f(1) = f(-1) = 1
Therefore, f is not one-one.
Now, an element 2 in co-domain R.
We can see that there does not exist any x in domain R such that
f(x) = 2
Therefore, f is not onto.
Therefore, function f is neither one-one nor onto.
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